GB2060122A

GB2060122A - Hot-gas Reciprocating Machine

Info

Publication number: GB2060122A
Application number: GB8025659A
Authority: GB
Original assignee: Philips Gloeilampenfabrieken NV
Current assignee: Koninklijke Philips NV
Priority date: 1979-08-10
Filing date: 1980-08-06
Publication date: 1981-04-29
Also published as: SE8005591L; IT8024055A0; IT1132350B; NL7906115A; FR2463259A1; JPS5629038A; DE3027602A1

Abstract

In a hot-gas reciprocating machine comprising two intercommunicating spaces of variable volume and two piston-like bodies (1 and 11) for varying the volumes of these spaces, the two bodies are coupled to two crank shafts (16 and 17) which are coupled to each other by a gearwheel mechanism by means of which the phase angle of the piston-like bodies can be varied by relative rotation of the crank shafts. The gearwheel mechanism comprises a plurality of gearwheels which mesh with one another and which include a first gearwheel (20) meshing with a gearwheel (18) fixed on one crank shaft (16) and a second gearwheel (21) meshing with a gearwheel (19) fixed on the other crank shaft (17). The gearwheel mechanism is mounted on a yoke (22) which is supported by two arms (23 and 24) which are each rotatable at one end about a respective one of the crank shafts and at the other end about the axis of a respective one of the first and second gearwheels. Means (40 to 44) are provided for varying the position of the yoke so as to alter the phase angle between the gearwheels on the crank shafts through the first and second gearwheels. <IMAGE>

Description

SPECIFICATION Hot-gas Reciprocating Machine The invention relates to a hot-gas reciprocating machine comprising first and second spaces of variable volume and first and second piston-like bodies for varying the volumes of the first space and second spaces respectively, the first and second piston-like bodies being respectively coupled to first and second crank shafts on each of which a gear wheel is rigidly mounted, said gearwheels being coupled to each other by a gearwheel mechansim in such a way that the two piston-like bodies are movable with phase difference, and means being provided for varying the phase angle between the two piston-like bodies by relative rotation of the crank shafts.

The expression "piston-like body" is to be understood to include a piston.

A hotgas reciprocating machine of the above construction is known from United States Patent Specification 2,508,315. This patent specification describes a hot gas engine of the displacer type in which the piston and the displacer are each coupled to a crank shaft. Each of the crank shafts comprises a bevel gearwheel which cooperates with a gearwheel on a third shaft. The crank shafts can be rotated somewhat with respect to each other by shifting this third shaft in the axial direction, thus resulting in a variation of the phase angle between piston and displacer and hence a variation of the power delivered by this machine.

The use of expensive bevel gearwheels and the comparatively large force required for the shifting of the third shaft are drawbacks of this known machine.

According to the invention there is provided a hot-gas reciprocating machine comprising first and second spaces of variable volume and first and second piston-like bodies for varying the volumes of the first and second spaces respectively, the first and second piston-like bodies being respectively coupled to first and second crank shafts on each of which a gearwheel is rigidly mounted, said gearwheels being coupled to each other by a gearwheel mechanism in such a way that the two piston-like bodies are movable with a phase difference, and means being provided for varying the phase angle between the two piston-like bodies by relative rotation of the crank shafts, wherein the gearwheel mechanism between the two gearwheels on the crank shafts comprises a plurality of further gearwheels which mesh with one another and which include a first further gearwheel which meshes with the gearwheel on the first crank shaft and a second further gearwheel which meshes with the gearwheel on the second crank shaft, the further gearwheels being rotatably mounted on a yoke which is supported by two arms of which one is rotatable at one end about the axis of the first crank shaft and relative to this shaft and at the other end about the axis of the first further gearwheel and relative to this gearwheel and to the yoke, and of which the other arm is rotatable at one end about the axis of the second crank shaft and relative to this shaft and at the other end about the axis of the second further gearwheel and relative to this gearwheel and to the yoke, means being provided for varying the position of the yoke.

The invention thus provides a hot-gas reciprocating machine in which the means for varying the phase difference between the movements of the two piston-like bodies have a simple construction and can be readily operated.

Embodiments of the invention will be described in detail hereinafter with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a part-elevation, part-perspective view of a phase-controlled single-acting hot-gas engine comprising two crank shafts which rotate in opposite directions, Figure 2 shows an alternative arrangement of the gearwheel mechanism of the engine shown in Figure 1, and Figure 3 shows a gearwheel mechanism for a similar engine which comprises two crank shafts which rotate in the same directions.

Figure 1 shows diagrammatically a phasecontrolled single-acting hot-gas engine comprising two pistons 1 and 11, which are connected to crank shafts which rotate in opposite directions. The first piston 1 is connected to a crank pin 5 via a piston rod 2, a guide piston 3 and a drive rod 4. The piston 1 is reciprocable in a cylinder 6 to vary with its upper side the volume of a space in the cylinder, which space is connected, via a heater 7, a regenerator 8 and a cooler 9, to a space in a second cylinder 10 in which the second piston 11 is reciprocable.

The second piston 11 is capable of varying with its lower side the volume of said space in the second cylinder 10, which space communicates with the spaces above and below the first piston 1 in the cylinder 6. The pistion 11 is connected to a crank pin 1 5 by way of a piston rod 12, a guide piston 13 and a drive rod 14. The crank pin 5 is rigidly connected to a first crank shaft 16, and the crank pin 1 5 is rigidly connected to a second crank shaft 17.

The crank shafts 16 and 17 are coupled to each other via a train of gearwheels 1 8, 1 9 20 and 21 in such a way that the two shafts rotate in opposite directions and also that the piston 1 reaches its uppermost position at an instant at which the piston 11 is still spaced at an angle , the phase angle, from its lowermost position.

The shafts of the gearwheels 20 and 21 are journalled in a yoke 22 which is supported by two arms 23 and 24 which are each rotatable at one end about the crank shaft 1 6 or 17 respectively and at the other end about the shaft of the gearwheel 20 or 21 respectively.

The arm 23 is rigidly connected to a further arm 40 which is rotatable about the crank shaft 16 and which is connected, via a coupling member 41, to a piston rod 42 of a piston 43 of a linear hydraulic or pneumatic motor 44.

Parallel to the first crank shaft 1 6 there is arranged a first auxiliary shaft 26 which is coupled, via a gearwheel 27 and the gearwheel 18, to the crank shaft 16.

Parallel to the second crank shaft 1 7 there is arranged a second auxiliary shaft 28 which is coupled, via a gearwheel 29 and the gearwheel 19, to the second crank shaft.

For the balancing of this hot-gas engine, counterweights 30, 34 and 31,35 are provided on the first and second crank shafts respectively.

Further counterweights 32 and 33 are provided on the auxiliary shafts 26 and 28. The masses of the counterweights and their distances from their axes of rotation are such that the first order forces and torques are fully balanced for a given phase angle.

The phase angle between the motions of the pistons 1 and 11 can be varied by turning, by means of the linear motor 44, the arm 40 and hence the arm 23 around the crank shaft 1 6. As a result, the gearwheel 20 rolls on the gearwheel 18, which is fixed on the crank shaft 16, so that the gearwheel 21 and hence also the gearwheel 19, which is fixed on the crank shaft 17, are also rotated through a given angle with respect to the gearwheel 18. The angular positions of the gearwheels 1 8 and 19 with respect to each other about their rotational axes is thus varied. As a result of the linkage 22, 23, 24, and the machine frame (not shown) between the crank shafts 1 6 and 17, the four relevant gearwheels 18, 20, 21, 1 9 will always remain in mesh with one another.

Figure 2 shows diagrammatically an alternative arrangement of the gearwheel mechanism, namely the gearwheels 20 and 21, by which the gearwheels 18 and 1 9 on the crank shafts are coupled to each other. This arrangement has the same advantages as the arrangement shown in Figure 1.

Finally, Figure 3 shows diagrammatically how two gearwheels 48 and 49 on crank shafts 16 and 1 7 which rotate in the same direction can be coupled by means of a gearwheel mechanism consisting of three gearwheels 45, 46 and 47 which are mounted on a yoke 22. Variation of the phase angle between the two crank shafts is effected in a similar manner to that described above for the constructions shown in Figures 1 and 2.

The gearwheels on the yoke 22 are all shown to have the same size, but this is not necessary; if desired, gearwheels of different diameter may also be used.

Claims

1. A hot-gas reciprocating machine comprising first and second spaces of variable volume and first and second piston-like bodies for varying the volumes of the first and second spaces respectively, the first and second piston-like bodies being respectively coupled to first and second crank shafts on each of which a gearwheel is rigidly mounted, said gearwheels being coupled to each other by a gearwheel mechanism in such a way that the two piston-like bodies are movable with a phase difference, and means being provided for varying the phase angle between the two piston-like bodies by relative rotation of the crank shafts, wherein the gearwheel mechanism between the two gearwheels on the crank shafts comprises a plurality of further gearwheels which mesh with one another and which include a first further gearwheel which meshes with the gearwheel on the first crank shaft and a second further gearwheel which meshes with the gearwheel on the second crank shaft, the further gearwheels being rotatably mounted on a yoke which is supported by two arms of which one is rotatable at one end about the axis of the first crank shaft and relative to this shaft and at the other end about the axis of the first further gearwheel and relative to this gearwheel and to the yoke, and of which the other arm is rotatable at one end about the axis of the second crank shaft and relative to this shaft and at the other end about the axis of the second further gearwheel and relative to this gearwheel and to the yoke, means being provided for varying the position of the yoke.

2. A hot-gas reciprocating machine as claimed in Claim 1 and substantially as herein described with reference to Figure 1, 2 or 3 of the accompanying drawings.