US3108578A - Rotary piston engine - Google Patents

Description

Oct. 29, 1963 H. o. SCHERENBERG 3,108,578

ROTARY PISTON ENGINE Filed Feb. 8, 1962 2 Sheets-Sheet 1 FIG. I

INVENTOR. HANS O. SCHERENBERG BY M M A TTORNEYS.

Oct. 29, 1963 Filed Feb. 8, 1962' H. O. SCHERENBERG ROTARY PISTON ENGINE 2 Sheets-Sheet 2 INVENTOR. HANS 0. SCHERENBERG xDw M637 ATTORNEYS.

United States Patent F 3,108,578 RGTARY PETGN ENGENE Hans 0. dcherenberg, Stuttgart-Heninaden, Germany,

assignor to Daimler-Benz Ahtiengesellschaft, Stuttgart- Unterturlrheim, Germany Filed Feb. 3, M62, Ser- No. 171,929 Ciaiins priority, application Germany Mar. 16, 1961 ii Claims. or. res-s The present invention relates to a rotary piston internal combustion engine of trochoidal construction provided with a piston carrying out a rotary movement about an eccentric arranged at the output shaft, in which, for purposes of achieving the rotary movement of the piston at least a trochoidally-shaped guide cam is arranged at the housing or at the piston and guide rollers are provided at the piston or at the housing, respectively, cooperating with this guide cam track.

In order to achieve the required predetermined rotational speed ratio of the output shaft and of the piston as required for practical operation of rotary piston internal combustion engines of trochoidal construction, it has been proposed heretofore to substitute, for the known transmission consisting of an internally toothed gear and an externally toothed gear wheel, the arrangement of trochoidally shaped cam tracks and guide rollers cooperating therewith in order to gain space for output or driven shafts of larger diameter.

The present invention aims at a further advantageous development and improvement of such transmissions consisting of cam tracks and guide rollers, and essentially consists in subdividing the cam track into two partial cam tracks disposed one behind the other in the axial direction of the engine and cooperating with pairs of guide rollers whereby one partial cam track is in operative engagement with the one guide roller of the pair of guide rollers when high roller rotational speeds occur during rotation of the piston whereas the other partial cam track is in operative engagement with the other guide roller of the pair of guide rollers when relatively small roller rotational speeds occur.

As a guide roller runs along a cam track, there is imparted to the guide roller by reason of relatively large rotational speed differences that occur considerable accelerations and decelerations which may affect adversely the cam track of the guide roller and which jeopardize a safe guidance. The accelerations and decelerations acting on a guide roller of the pair of guide rollers are reduced to such a considerable extent by the present invention that harmful effects on the guide rollers need no longer be expected.

According to a further feature of the present invention, the surface portions of the partial cam tracks which during certain phases of operation do not engage or come into contact with the guide rollers may be set back or undercut with respect to the other surface portions, for example, may be machined or ground by appropriate machinery to the desired undercut or set back.

In order not to impair the guidance when the guidance is given up by or transferred from one guide roller to the other, the beginning and end of the non-set back or nonundercut surface portions of the partial cam tracks may be in operative connection with each other by web portions which come in contact or engage both guide rollers of a respective pair. The length and positions of these web portions may thereby be so selected that the accelerations and decelerations of the guide rollers are reduced to a minimum.

Accordingly, it is an object of the present invention to provide a transmission consisting of cam tracks and guide rollers for imparting to a rotary piston internal combustion engine of trochoidal construction the required rota- Patented Oct. 29, 1963 tional speed ratio between piston and output shaft which efiectively eliminates the shortcomings encountered with the prior art constructions by simple means that may be readily manufactured without entailing substantial expenditures.

Another object of the present invention resides in the provision of a rotary piston internal combustion engine of trochoidal construction provided with transmission means consisting of cam tracks and guide rollers for imparting to the rotary piston the desired speed relative to the speed of the driven shaft in which the accelerations and decelerations acting on the guide rollers are considerably reduced so as to minimize if not completely eliminate the harmful elfects that would otherwise occur at the cam tracks and/ or guide rollers without impairing a safe and reliable guidance.

A further object of the present invention resides in the provision of a rotary piston internal combustion engine provided with transmission means consisting of cam track means and guide roller means for establishing the predetermined rotary speed relative to the output shaft in which means are provided to assure proper guidance notwithstanding the subdivision of the cam tracks into partial cam track. sections.

These and other objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, one embodiment in accordance with the present invention, and wherein FIGURE l is a cross sectional view through a rotary piston internal combustion engine of the type to which the present invention relates;

FlGURE 2 is an elevational view, on an enlarged scale, and partially in cross section, taken in the direction of arrow II of FIGURE 1 and illustrating the cam track arrangement in accordance with the present invention, and

FIGURE 3 is an elevational view taken at right angles to FIGURE 2 in the direction of arrow III of FIGURE 2.

Referring now to the drawing wherein like reference numerals are used throughout the various views to designate corresponding parts, and more particularly to FIGURE 1, the triangularly-shaped piston 2 is arranged on an eccentric of the driven or output shaft 1 so as to rotate in the direction of arrow 3 within the housing 5 provided with a two-arched cam surface or track 4. In order to achieve a rotary movement of the piston 2 on the eccentric relative to the driven shaft 1 with the value of /3 of the angular velocity of the shaft 1 required for proper operation of the illustrated embodiment, there is provided, instead of the usual gear transmission, the trochoidally-shaped cam track 6 arranged at one housing side wall, possibly another cam track being also arranged at the oppositely disposed housing side wall, which cam track 6 cooperates with pairs of guide rollers 7 supported at the piston 2.

As shown in detail in FIGURES 2 and 3, the cam track generally designated by reference numeral 6 which is secured with the side wall 8 thereof at the housing side wall in any suitable manner, consists of the two partial cam track sections 6' and 6" disposed one behind the other in the axial direction. The guide roller '7' of the pair of guide rollers generally designated by reference numeral 7 cooperates with the partial cam track section 6' and the guide roller 7" of the pair of guide rollers 7 cooperates with the partial cam track section 6". In the illustrated embodiment three pairs of guide rollers 7 are provided though, of course, the number of guide roller pairs may be varied. The pairs of guide rollers 7 are rotatably supported in any suitable manner known in the prior art on hearing bolt members or bearing pins 9 which in turn are supported at the lateral guide ring secured at the piston.

Both partial cam track sections 6' and 6" are provided with surface portions which come into engagement or contact with the guide rollers '7' and 7" during rotation of the piston. These surface portions which will be referred to as active surface portions are designated on the cam track section 6 by reference numeral 11 and on the cam track portion 6 by reference numeral 12. Additionally, the cam track sections 6' and 6" are provided with set-back or undercut surface portions which do not come into engagement with the guide rollers 7' and 7" during rotation of the piston. These surface portions which will be referred to as inactive surface portions are designated in connection with the partial cam track section 6 by reference numeral 11' and in connection with the partial cam track portion 6" by reference numeral 12.

The active surface portions 11 at the partial cam track section 6 are disposed within an area in which relatively high rotational speeds occur on the part of the guide roller member 7' whereas the active surface portions 12 at the partial cam track section 6" are disposed within an area in which relatively low rotational speeds of the guide rollers 7 occur.

The non-set back surface portions, i.e., the active surface portions 11 and 12 along which are guided the guide rollers 7 and 7", are connected with each other at the beginning and end thereof by web portions 13 along which are guided simultaneously both guide rollers 7 and 7". The length of these web portions 13 in the circumferential direction and the respective position of these web portions are appropriately so selected that decelerations and accelerations of the guide rollers are reduced to a minimum.

During rotation of the piston, the latter is guided by means of the guide roller 7 along the surface portion 11 of the partial track section 6 whereas, at the same time, the guide roller 7" passes freely over the set-back surface portion 12' of the partial cam track section 6". Upon reaching the web portion 13 both guide rollers 7' and 7" of each guide roller pair 7 carry out a guide function, and upon leaving the web portion 13 the guide roller 7" takes over the guidance along the surface portion 12 of the partial track section 6" whereas at the same time the guide roller 7' passes freely over the set-back surface portion 11 of the partial cam track section 6.

While I have shown and described one embodiment in accordance with the present invention, it is understood that the same is not limited thereto, but is susceptible of many changes and modifications within the spirit and scope thereof, and I therefore do not wish to be limited to the details shown and described herein, but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

I claim:

1. A rotary piston internal combustion engine of trochoidal construction comprising housing means, output shaft means provided with eccentric means, piston means carrying out a rotary movement within said housing means about said eccentric means, and means including trochoidally-shaped cam means at one of the two parts consisting of said housing means and said piston means and guide roller means at the other of said two parts cooperating with said cam means for imparting to said piston means a predetermined relative rotary movement with respect to said output shaft means, said guide roller means including a plurality of pairs of guide rollers, said cam means being subdivided into two partial cam sections cooperating with pairs of guide rollers, said partial cam sections being disposed one behind the other in the axial direction of the engine, one of said partial cam sections being in operative engagement with one guide roller of a respective pair of guide rollers during occurrence of relatively large roller rotational speeds upon rotation of the piston means and the other partial cam section being in operative engagement with the other guide roller of a respective pair during the occurrence of relatively small roller rotational speeds upon rotation of said piston means.

2. A rotary piston internal combustion engine of trochoidal construction comprising housing means, output shaft means provided with eccentric means, piston means carrying out a rotary movement within said housing means about said eccentric means, and means including trochoidally-shaped cam means at one of the two parts consisting of said housing means and said piston means and guide roller means at the other of said two parts cooperating with said cam means for imparting to said piston means a predetermined relative rotary movement with respect to said output shaft means, said guide roller means including a plurality of pairs of guide rollers, said cam means being subdivided into two partial cam sections eooperating with pairs of guide rollers, said partial cam sections being disposed one behind the other in the axial direction of the engine.

3. A rotary piston internal combustion engine of troehoidal construction comprising housing means, output shaft means provided with eccentric means, piston means carrying out a rotary movement within said housing means about said eccentric means, and means including trochoidally-shaped cam means at one of the two parts consisting of said housing means and said piston means and guide roller means at the other of said tWo parts cooperating with said cam means for imparting to said piston means a predetermined relative rotary movement with respect to said output shaft means, said guide roller means including a plurality of pairs of guide rollers, said cam means being subdivided into two partial cam sections cooperating with pairs of guide rollers, said partial cam sections cooperating with pairs of guide rollers, said partial cam sections being disposed one behind the other in the axial direction of the engine, one of said partial cam sections being in operative engagement with one guide roller of a respective pair of guide rollers during occurrence of relatively large roller rotational speeds upon rotation of the piston means and the other partial cam section being in operative engagement with the other guide roller of a respective pair during the occurrence of relatively small roller rotational speeds upon rotation of said piston means, the inactive surface portions of the partial cam sections which remain out of contact with said guide rollers being set-back with respect to the active surface portions coming into engagement with said guide rollers.

4. A rotary piston internal combustion engine of trochoidal construction comprising housing means, output shaft means provided with eccentric means, piston means carrying out a rotary movement within said housing means about said eccentric means, and means including trochoidally-shaped cam means at one of the two parts consisting of said housing means and said piston means and guide roller means at the other of said two parts cooperating with said cam means for imparting to said piston means a predetermined relative rotary movement with respect to said output shaft means, said guide roller means including a plurality of pairs of guide rollers, said partial cam sections being disposed one behind the other in the axial direction of the engine, one of said partial cam sections being in operative engagement with one guide roller of a respective pair of guide rollers during occurrence of relatively large roller rotational speeds upon rotation of the piston means and the other partial cam section being in operative engagement with the other guide roller of a respective pair during the occurrence of relatively small roller rotational speeds upon rotation of said piston means, and the beginning and end of the active surface portions of the partial cam sections being operatively connected with each other by web portions operative to engage both guide rollers of a respective guide roller pair.

5. In a rotary piston internal combustion engine having a housing, a rotary piston adapted to carry out a rotary movement within said housing about an eccentric provided at the output shaft, and transmission means consisting of cam means and guide roller means for imparting to said rotary piston a predetermined relative rotary movement with respect to said output shaft, the improve-. ment essentially consisting of subdividing said cam means into several partial cam sections disposed one behind the other in the axial direction of the engine, each guide roller means being constituted by several guide rollers, each guide roller of a respective guide roller means cooperating with a respective partial cam section in such a manner as to minimize accelerations and decelerations on the part of said rollers.

6. A rotary piston internal combustion engine of trochoidal construction comprising housing means, output shaft means provided with eccentric means, piston means carrying out a rotary movement within said housing means about said eccentric means, and means including trochoidally-shaped cam means at one of the two parts consisting of said housing means and said piston means and guide roller means at the other of said two parts cooperating with said cam means for imparting to said piston means a predetermined relative rotary movement with respect to said output shaft means, said guide roller means including a plurality of pairs of guide rollers, said cam means being subdivided into two partial cam sections cooperating with pairs of guide rollers, said partial cam sections being disposed one behind the other in the axial direction of the engine, one of said partial cam sections being in operative engagement with one guide roller of a respective pair of guide rollers during occurrence of relatively large roller rotational speeds upon rotation of the piston means and the other partial cam section being in operative engagement with the other guide roller of a respective pair during the occurrence of relatively small roller rotational speeds upon rotation of said piston means, the inactive surface portions of the partial cam sections which remain out of contact with said guide rollers being set-back with respect to the active surf-ace portions coming into engagement with said guide rollers, and the beginning and end of the active surface portions of the partial earn sections being operatively connected with each other by web portions operative to engage both guide rollers of a respective guide roller pair.

7. In a rotary piston internal combustion engine having a housing, a rotary piston adapted to carry out a rotary movement within said housing about an eccentric provided at the output shaft, and transmission means consisting of cam means and guide means cooperating with said cam means for imparting to said rotary piston a predetermined relative rotary movement with respect to said output shaft, the improvement essentially consisting in subdividing said cam means into partial cam means, each guide means including a plurality of guide roller means, a respective guide roller means cooperating with a corresponding partial cam means in such a manner as to minimize accelerations and decelerations on the part of said roller means.

8. A rotary piston internal combustion engine of trochoidal construction comprising housing means, output shaft means provided with eccentric means, piston means carrying out a rotary movement within said housing means about said eccentric means, means including troehoidallyshaped cam means at one of the two parts consisting of said housing means and piston means and guide roller means at the other of said two parts cooperating with said cam means for imparting to said piston means the predetermined relative rotary movement with respect to said output shaft means, and means in at least one of said cam and guide means for minimizing accelerations and decelerations of said guide means.

9. in a rotary piston internal combustion engine having a housing, a rotary piston adapted to carry out a rotary movement within said housing about an eccentric provided at the output shaft, and transmission means consisting of cam means and guide roller means for imparting to said rotary piston a predetermined relative rotary movement with respect to said output shaft, the improvement essentially consisting of means operatively associated with said cam means and guide roller means to minimize accelerations and decelerations on the part of said roller means.

10. A rotary piston internal combustion engine of trochoidal construction comprising housing means, output shaft means provided with eccentric means, piston means carrying out a rotary movement within said housing means about said eccentric means, means including trochoidallyshaped cam means at one of the two parts consisting of said housing means and piston means and guide roller means at the other of said two parts cooperating with said cam means for imparting to said piston means the predetermined relative rotary movement with respect to said output shaft means, and means in said cam and guide means for minimizing accelerations and decelerations of said guide means including a plurality of partial cam sections in said cam means cooperating with guide rollers of said guide means;

11. ,A rotary piston internal combustion engine of trochoidal construction comprising housing means, output shafit means provided with eccentric means, piston means carrying out a rotary movement within said housing means about said eccentric means, means including trochoidally-shaped cam means at one of the two parts consisting of said housing means and piston means and guide roller means at the other of said two parts cooperating with said cam means for imparting to said piston means the predetermined relative rotary movement with respect to said output shaft means, and means in said cam and guide means tor minimizing accelerations and decelerations of said guide means including a plurality of partial cam sections in said cam means cooperating with guide rollers of said guide means, said cam sections being disposed one behind the other in the axial direction of the engine and being so arranged and constructed that one of said cam sections is in operative engagement with one guide roller during occurrence of relatively large roller rotational speeds upon rotation of the piston means and another cam section is in operative engagement with another guide roller during the occurrence of relatively small roller rotational speeds upon rotation of said piston means.

No references cited.

Claims (1)

1. A ROTARY PISTON INTERNAL COMBUSTION ENGINE OF TROCHOIDAL CONSTRUCTION COMPRISING HOUSING MEANS, OUTPUT SHAFT MEANS PROVIDED WITH ECCENTRIC MEANS, PISTON MEANS CARRYING OUT A ROTARY MOVEMENT WITHIN SAID HOUSING MEANS ABOUT SAID ECCENTRIC MEANS, AND MEANS INCLUDING TROCHOIDALLY-SHAPED CAM MEANS AT ONE OF THE TWO PARTS CONSISTING OF SAID HOUSING MEANS AND SAID PISTON MEANS AND GUIDE ROLLER MEANS AT THE OTHER OF SAID TWO PARTS COOPERATING WITH SAID CAM MEANS FOR IMPARTING TO SAID PISTON MEANS A PREDETERMINED RELATIVE ROTARY MOVEMENT WITH RESPECT TO SAID OUTPUT SHAFT MEANS, SAID GUIDE ROLLER MEANS INCLUDING A PLURALITY OF PAIRS OF GUIDE ROLLERS, SAID CAM MEANS BEING SUBDIVIDED INTO TWO PARTIAL CAM SECTIONS COOPERATING WITH PAIRS OF GUIDE ROLLERS, SAID PARTIAL CAM SECTIONS BEING DISPOSED ONE BEHIND THE OTHER IN THE AXIAL DIRECTION OF THE ENGINE, ONE OF SAID PARTIAL CAM SECTIONS BEING IN OPERATIVE ENGAGEMENT WITH ONE GUIDE ROLLER OF A RESPECTIVE PAIR OF GUIDE ROLLERS DURING OCCURRENCE OF RELATIVELY LARGE ROLLER ROTATIONAL SPEEDS UPON ROTATION OF THE PISTON MEANS AND THE OTHER PARTIAL CAM SECTION BEING IN OPERATIVE ENGAGEMENT WITH THE OTHER GUIDE ROLLER OF A RESPECTIVE PAIR DURING THE OCCURRENCE OF RELATIVELY SMALL ROLLER ROTATIONAL SPEEDS UPON ROTATION OF SAID PISTON MEANS.

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