US3538357A - Fluid circulating apparatus for reciprocating machines - Google Patents

Description

' FLUID CIRCULATING APPARATUS FOR RECIPROCATING MACHINES Filed Jan. 2, 1969 Nov. 3, 1970 M. BARTHALON' 3 Sheets-Sheet 1 Nov; 3, 197.0 M. BARTI- IALON 3,538,357

FLUID CIRCULATING APPARATUS FOR RECIPROCATING MACHINES 3 Sheets-Sheet 2 Filed Jan. 2, 1969 5y km 1 (7M HTrY- United States Patent Int. Cl. H02r 9/19 US. Cl. 310-16 13 Claims ABSTRACT OF THE DISCLOSURE Machine having reciprocating movement comprising a base, a stator mounted on this base, a reciprocating movement assembly lodged in this stator and having reciprocating movement with respect to the latter, and a device for circulating within the machine a fluid, more particularly a liquid. The machine is characterized in that said device comprises a chamber having a delivery orifice for the fluid and means for causing the fluid to move by inertia, said means comprising a surface belonging to said chamber, movable with respect to the base, and arranged so as to cause the fluid to pass from the chamber to another region of the machine.

The'present invention concerns a machine having reciprocating movement and comprising an oscillating moving assembly and a means for the circulation within the machine of a fluid, more particuarly a liquid. This liquid may be especially the auxiliary liquid used for the lubrication or the cooling of the machine or of an associated machine. However, the remarkable features of the invention allow it to be used to make a particularly simple pump having variable stroke.

- The invention is advantageously but not limitatively applied to reciprocating, variable stroke, linear energy converters, for example of the electro-motor type described especially in US. Pat. No. 3,461,806 for Reciprocating Electric Motor. The invention also applies to linear energy converters in particular of the motor-alternator type, more particularly those which are the subject of the applicants application for a Pat. 594,191 filed November 14, 1966 for Electromagnetic Machines. As these machines are often of low unit power and are intended to be manufactured in large quantities at moderate prices, they need lubrication and/ or cooling arrangements which are robust, cheap and adapted to the variable stroke of the machine.

Normal reciprocating pumps having suction and deliv ery valves, driven by the movement of the oscillating assembly are too costly for this type of machine, and furthermore, are incapable of delivering a suflicient output when the stroke of the machine is small.

The cost of rotary or reciprocating pumps driven by an independent motor would be prohibitive for machines of limited unit power.

Also known are circulation means, in which an intermittent rotary movement is derived from the oscillating movement of the moving assembly which drive a pump through a free wheel. These systems are costly, complex and of uncertain reliability.

The present invention is intended to remedy these difficulties and to allow reciprocating machines to be manufactured which comprise a means for the circulation of the fluid which will be simple and of very low cost price. According to the invention, the reciprocating movement machine, which comprises a base, a stator mounted on this base, a moving assembly lodged within the stator and having reciprocating movement with re- 3,538,357 Patented Nov. 3, 1970 spect to the latter and a device for circulating within the machine a fluid, more particularly a liquid, is characterised in that said device comprises a chamber having a delivery orifice for the fluid and means for causing the fluid to move by force of inertia, comprising a surface in the chamber, movable with respect to said base and arranged so as to cause the fluid to pass from said chamber to another region of the machine.

Thanks to the use of this movable surface, the means for circulation of the fluid is thus very simple and reliable. The fluid circulating in the machine is more especially a liquid, such as an auxiliary liquid ensuring the lubrication of the machine.

According to one embodiment of the invention which is applicable to reciprocating movement machines of low power, and in the case where the fluid is a liquid, the stator is elastically mounted with respect to the base such that it is submitted to a reciprocating movement relative to the base by the reaction of the moving assembly, and the chamber is connected to the stator such that its surfaces ensure the propulsion of the liquid by the forces of inertia.

According to another embodiment of the invention applicable to reciprocating movement machines of greater power, comprising a moving assembly having linear reciprocating motion, this assembly has a chamber having an axis parallel to the direction of movement of said assembly and in which is mounted a secondary moving assembly comprising a plunger moving under the effect of the forces of inertia along the axis of said chamber and substantially sealing the same. The plunger defines in the chamber at least one variable volume which is connected alternately to an intake channel connected to a reservoir of liquid and to a delivery channel.

This embodiment provides a greater flow of liquid than the preceding one while being particularly simple and sure.

According to another embodiment of the invention, applicable to medium power reciprocating movement machines, the device for circulating the liquid comprises a chamber forming a dispenser for the liquid, in unit with the moving assembly and formed by a tubular piece inclined with respect to the axis of movement of this assembly. The lower part of this dispenser is pierced with an orifice which is dipped in the liquid contained in the reservoir, whereas its upper part has a smaller section orifice for the distribution of the liquid.

Other features of the invention will appear from the following description:

On the attached drawings, given as non-limitative examples, are represented several embodiments of the invention:

FIG. 1 is an axial section view of the machine conforming to the invention.

FIG. 2 is a view of the same machine on section IIII of FIG. 1.

FIG. 3 is an axial section of a second embodiment of the invention.

FIG. 4 is a view of the machine represented on FIG. 3 with section IV-IV of FIG. 3.

FIG. 5 is a section view of a modification of the embodiment according to FIG. 4.

FIG. 6 is an axial section view of a third embodiment of the invention. 1

FIG. 7 is a corresponding view with section on VII- VII of FIG 6.

air which includes a cylinder 1 within which is guided a sliding part in the form of a piston 2 driven by a linear reciprocating electro-magnetic motor 3 of a similar type to that described in US. Pat. No. 3,461,806 for Reciproeating Electric Motor," filed by the applicant. The clearance between the cylinder 1 and piston 2 is preferably between 2 and 50 microns. The assembly of the motor 3 and cylinder 1 forms the stator of the machine which is mounted on a fixed base 4 by means of elastic suspension strips 5 which are capable of being deformed in a direction parallel to the axis of the machine.

In the embodiment, the fluid is an auxiliary liquid forming the lubricating oil whose circulation is ensured, in accordance with the invention, by means which comprise a chamber forming an oil reservoir 6 disposed in the lower part of cylinder 1 and communicating with a delivery orifice in the form of an annular groove 7, practiced in the internal surface of cylinder 1, and entering the cylinder in the region of the mid point of the surface swept by piston 2 and at a distance from the cylinder head at least equal to the cylinder bore. The groove 7 also communicates with a drilling 9 in which the level gauge 11 is housed (FIG. 2) and with a filling orifice 12 closed by a blank 13. This blank is itself drilled with a passage 14 closed by a block 15 of porous material through which air can pass but not oil.

In a low power machine of this type, the oscillating moving assembly, of which piston 2 forms a part, is not dynamically balanced, such that in operation the stator of the machine has a reciprocating movement provoked by reaction of the moving assembly and in phase opposition with the latter, the amplitudes of these two movements being inversely proportional to the corresponding masses. The sufaces of reservoir 6 are thus subjected to a periodic acceleration whose value is maximum at the moment when the speed of the stator changes direction. The oil contained in reservoir 6 is thus projected by the forces of inertia onto the end walls 16 and 17 which thus exercise a pressure on the oil and part of the oil projected mounts progressively towards the groove 7, this progression being aided by the action of the surface tension of the oil. A continuous film of oil is thus established between the surface of cylinder 1 and piston 2, this film being renewed at each stroke of the piston. The small clearance between these two surfaces prevents air leakage and limits the delivery of oil during operation; furthermore it prevents oil leakage during transport of the machine when it may be temporarily inverted.

The permeability to air of porous block 15 maintains in reservoir 6 a pressure equal to the atmopheric pressure, which prevents oil from being driven up towards the compressor while its practically zero permeability to oil prevents the latter from escaping to the outside.

Due to the position of the groove 7 near the centre of the surface swept by piston 2, the leakage path for air compressed at the end 18 of cylinder 1 when piston 2 is at the outer dead point, is suificient long to prevent this air from escaping through reservoir 6.

Measurements have been made on an air electro-compressor of 250 watts and 32 millimeters cylinder equipped with a lubricating means of the type described. The oil consumption measured during a long endurance test corresponding to .00001 (one hundred thousandth) of the weight of air delivered by the compressor, the delivery being 30 litres per minute at a pressure of 3.5 kg./cm. Wear measured after 1000 hours of operation was practically negligible.

In machines of much higher power in which the moving assembly is dynamically balanced, the system just described cannot be used because the stator of these machines is practically motionless. FIGS. 3 to 5 illustrate another embodiment of the invention applicable to this range of machines, which also gives a higher delivery of oil.

The machine represented is a linear motor-compressor intended for the compression of expensive or dangerous gases. This motor-compressor is suspended by links 31, within a sealed casing 32, whose lower part 33 forms the reservoir of auxiliary liquid which in this case again, is the lubricating oil of the machine. The moving assembly of the compressor comprises a piston 34 having a reciprocating movement within a cylinder 35.

Within the stator, the moving assembly and the piston 34, is formed a cylindrical chamber 36 co-axial with this piston and in which a secondary moving assembly comprising a slide-block such as a plunger 37 moves freely. This plunger thus divides the chamber 36 into two volumes 36a and 36b, which are variable according to the position of the plunger. The clearance between the surfaces of the plunger 37 and of the chamber 36 are sufliciently small to make oil leakage from one volume to another negligible. Each of the volumes 36a and 36b is connected to the external surface of piston 34 by a radial orifice 38a, 38b drilled at a certain distance from the end surfaces 39a, 39b of the chamber 36 such that when the plunger 37 commences to block off one of these orifices 38a, 38b, there remains a residual volume between the face of this plunger and the corresponding surface 39a, 39b.

Furthermore, the orifice 38a is drilled at a certain distance from the end 46 of the piston 34, equal to at least the bore of the latter.

The internal surface of cylinder 35 also includes three annular grooves 41, 42a, 42b. The groove 41 is connected by an admission channel 43 to the oil reservoir 33. Grooves 42a and 42b symetrically arranged with respect to group 41, are connected by radial orifices 44a and 44b to a channel 45 for the delivery of oil in the machine. A core 40 blocks off the bore of piston 34 thus forming a cavity 36, after introduction of the plunger 37.

The operation of the device is as follows; it being assumed that piston 34 is at its outer dead point and is starting its stroke towards the inner dead point in direction of arrow 1 with a positive acceleration, the plunger 37 is forced by the inertia against the surface 39a of the volume 36a. In the second half of the stroke in direction 1 the magnitude of the speed decreases and therefore the acceleration becomes negative and the plunger 37 moves under the forces of inertia towards the surface 39b, compressing the oil contained in volume 36b and creating a partial vacuum in the volume 36a. Towards the end of the stroke of piston 34, in direction f, the orifice 38b lines up with the groove 42b and the orifice 38a with the groove 41. The oil contained in the volume 36b is delivered into the distribution channel 45, while oil is drawn from the reservoir 33 into volume 36a through channel 43. During the return stroke in direction g towards the outer dead point, the reverse takes place, the oil from volume 36a being discharged through channels 44a and 45, while oil is drawn in from reservoir 33 to the volume 36b. Thanks to this arrangement the channel 45 is fed with oil under pressure at each stroke of the piston 34.

When the plunger 37, towards the end of its stroke, closes off an orifice such as 38a, there remains between its forward face and the end wall 39a of the chamber 36 a residual volume full of oil which cannot escape and which very effectively damps the shock at the end of the stroke. Furthermore, due to the distance arranged between orifice 38a and the extremity 46 of the piston 34, compressed air leaks into the oil circuit are very small.

In the simplified version of FIG. 5, the radial orfice 38b drilled in the wall of chamber 36 has an opening beyond the extremity of the cylinder 35 when piston 34 is at its inner dead point (position shown in FIG. 5). In this position of piston 34, the oil is thus delivered directly to the extremity of cylinder 35, which allows the annular groove 42b and the radial orifice 44b which, in the application shown in FIG. 3, were formed in the internal surface of cylinder 35, to be eliminated.

Measurements have been carried out on an arrangement of this type mount on a 200 w. motor-compressor. The bore of the chamber 36 was 8 mm., the stroke of plunger 37 was mm., the intake pressure in volumes 36a and 36b was 100 grammes per cm. and the delivery pressure 800 grammes per cm. The clearance between the plunger 37 and the surface of the chamber 36 was several hundredths of a millimeter, which required no special precautions during machining. Under these conditions an oil delivery of 300 litres per hour was obtained.

It is understood that in the machine of the type considered, the fluid may be a gaseous medium, the machine then acting as a pump for this medium.

In the case where the machine is of too high a unit power to be able to use the embodiment represented in FIG. 1 and where it does not include an auxiliary piston as in the embodiment shown in FIG. 3, a third embodiment may advantageously be used, which will now be described, referring to FIGS. 6 to 10.

In the case represented on FIGS. 6 to 7, the machine is a variable reluctance motor-alternator, whose motor part includes motor pistons 61 and scavenge pistons 62, moving within cylinder 63 closed by cylinder heads 64 which carry sparking plugs 65. The pistons 62 are connected by a shaft 66, on which is fixed a magnetic armature 67, driven by this shaft in a reciprocating movement. This armature moves in air gaps 68 and 69 of a magnetic circuit which comprises two pole pieces 71a and 7112 joined by a common yoke 72. Each of these pole pieces carries an excitation coil 73a, 73b through which runs a direct current of appropriate sign, while a field coil 74 for generating the alternating current surrounds the assembly of the two pole pieces 71a, 71b.

The fixed parts of the machine such as the cylinder 63 and magnetic circuits are mounted on a hollow base in the form of a body 75.

In this embodiment the circulation of auxiliary liquid according to the invention is intended for cooling the coils. To this end a reservoir 76 for the cooling oil is formed in the lower part of the body 75 and the shaft 66 carries a chamber acting as oil dispenser 77 formed by a. tubular piece whose axis is inclined with respect to the direction of reciprocating movement of the moving assembly. The lower part 79 of the distributor 77 is open and dips into the oil of reservoir 76 while the upper part of the dispenser is drilled with an orifice 78 of smaller section than the central channel of the dispenser. A particularly inexpensive embodiment of dispenser 77 consists of forming it (FIG. 8) from a tube brazed to shaft 66, this tube being partially flattened such as to give an ovoid section (FIG. 9). At its upper end (FIG. 10) tube 77 is completely flattened over part of its diameter so as to form the output orifice 78 of a small section.

When the dispenser 77 moves away from coils 73a, 73b and 74 in the direction of arrow 1', with a speed which decreases as it moves away from the center of its stroke, represented by the line -AA (FIG. 6) and when it returns in direction h towards line AA with increasing speed, its acceleration is in the direction of h, that is towards the coils. Owing to the forces of inertia, the oil it contains tends to move with respect to it in the direction i and as a result of the slope of the axis of the dispenser, the oil rises within the latter. During the stroke of the dispenser 77 from the line AA towards the coils and back, the acceleration of the dispenser is, on the other hand, directed in the direction i and, owing to inertia the oil it contains and which has been raised up to the upper orifice 78 is projected in the inverse direction, that is towards the coils to be cooled. Experience shows that a very effective cooling spray of the coils is obtained.

The auxiliary liquid circulating means according to the invention may be advantageously employed on all machines of medium or low unit power, having reciprocating movement, thanks to its very low cost price and its certain operation, which requires practically no maintenance.

The application of this device is however especially advantageous in the case of linear energy converters having reciprocating moving assemblies in which the maximum values of the acceleration of the moving assemblies are greater than corresponding values observed in conventional machines having crankshaft and connecting rods. On FIG. 11 are shown the relationships of time and velocity in the course of one cycle observed on a crankshaft and connecting rod machine (curve A dotted), and in a convertor having a reciprocating moving assembly (curve B full line). In this figure the abscissa is the time t in milliseconds and the ordinate is the linear velocity of the moving assembly in meters per second. The accelerations are thus represented by the slope of the tangents to these two curves. In the first half of the cycle, and especially at the origin, the slope G of the tangent T to curve B is 35 to 40% greater than slope G of the tangent T to curve A. the inertia forces are consequently greater and the eflicacy of the device is higher in linear converters with reciprocating moving assemblies.

This effect is especially important in the machines described in the applicants patent cited above. In these machines the position of the moving assembly corre sponding to the beginning of the cycle is chosen such that the force of attraction exerted on this assembly by the electro-magnetic units will be high. The acceleration at the beginning of the cycle is thus even greater than is shown in FIG. 11 and the device for circulating fluid by inertia is correspondingly more effective.

It is understood that the invention is not limited to the embodiments which have just been described and that many variants of execution may be applied to them without going beyond the field of this invention. Thus in the last version represented, it would be possible to have two tubular distributors placed on each side of the armature 67 and having the upper orifices divided and directed towards the coils situated on each side of the air gaps. Such a device would allow the stator of the machine to be centered relative to the body 75.

I claim:

1. In a reciprocating machine including a base, a stator mounted on the base, and a reciprocating assembly guided :by and movable relative to the stator, fluid circulating apparatus comprising a chamber formed in the machine and adapted to receive a fluid, a delivery orifice for the chamber, surface means in the chamber movable relative to the base of the machine in response to reciprocation of the reciprocating assembly, said surface means formed to transmit to said fluid the forces of inertia generated as a result of said reciprocation, and guiding walls in the chamber movable with respect to the base and formed to guide the fluid towards the delivery orifice.

2. Fluid circulating apparatus according to claim 1, wherein means are provided for mechanically connecting the chamber for the fluid to the reciprocating assembly.

3. In a reciprocating machine includinga base, a stator mounted on the base, a reciprocating assembly guided by and movable with respect to the stator, and means to mount the stator resiliently with respect to the base to impart to the stator a reciprocating movement relative to the base upon reciprocation of the reciprocating assembly, liquid circulating apparatus comprising a chamber formedin the stator and adapted to receive a liquid, a delivery orifice for the chamber, at least one wall of the chamber being formed to transmit to the liquid the forces of inertia resulting from reciprocation of the reciprocating assembly, and guiding walls of the chamber movable with respect to the base and formed to guide the liquid towards the delivery orifice.

4. Liquid circulating apparatus according to claim 1, in which is provided a medium permeable to air and impermeable to the liquid, and means to vent the chamber to the atmosphere through said medium to maintain the chamber at atmospheric pressure while preventing leakage of the liquid therefrom.

5. In a reciprocating machine including a base, a stator mounted on the base, a guiding cylinder formed within the stator, and a reciprocating assembly including a piston reciprocating within the guiding cylinder, fluid circulating apparatus comprising a chamber formed in the machine and adapted to receive a fluid, a delivery orifice for the chamber, the orifice opening into the cylinder through the surface of the cylinder and being blocked by the piston during a portion of its reciprocating movement, surface means in the chamber movable relative to the base of the machine in response to reciprocation of the reciprocating assembly, said surface means formed to transmit to said fluid the forces of inertia generated as a result of said reciprocation, and guiding Walls in the chamber movable with respect to the base and formed to guide the fluid towards the delivery orifice.

6. Fluid circulating apparatus according to claim 5, wherein the delivery orifice opens into the middle part of the cylinder surface swept by the reciprocating movement of the piston.

7. In a reciprocating machine including a base, a stator mounted on the base, a reciprocating assembly guided by and movable with respect to the stator, a reservoir for fluid and a delivery passage for said fluid, fluid circulating apparatus comprising a chamber formed as a cylinder in the machine and having an axis parallel to the direction of movement of the reciprocating assembly, an orifice in the wall of said cylinder, a plunger movable within the chamber in response to the forces of inertia upon reciprocation of the reciprocating assembly, said plunger defining in said chamber at least one variable volume, and means for connecting said orifice during reciprocation of the reciprocating assembly alternately to the fluid reservoir and to the delivery passage.

8. Fluid circulating apparatus according to claim 7, in which the wall of said cylinder includes a second orifice, and means for connecting said second orifice during reciprocation of the reciprocating assembly alternately to the fluid reservoir and to the delivery passage.

9. Fluid circulating apparatus according to claim 8, in which said orifices are located in the Wall of said cylinder at positions remote from the end walls of the chamber, thereby providing at the ends of the chamber volumes serving as a damper for the plunger.

10. Fluid circulating apparatus according to claim 9, in which said orifices in the wall of said cylinder are located at a distance from the ends of said cylinder equal at least to the diameter of the bore of the cylinder.

11. In a reciprocating machine including a base, a stator mounted on the base, an external cylinder formed in a portion of the stator, a reciprocating assembly guided by and movable with respect to the stator, the assembly including a piston adapted to reciprocate in the external cylinder, fluid circulating apparatus comprising a chamber for the fluid formed as an internal cylinder in the piston coaxially with the external cylinder, a plunger movable in the internal cylinder by the forces of inertia resulting from reciprocation of the reciprocating assembly, first and second orifices extending from the internal cylinder through the piston, and passage means forming portions of fluid circuits in the stator and in the surface of the external cylinder, said orifices completing said fluid circuits when moved into coincidence with said passage means during reciprocation of the reciprocating assembly.

12. In a reciprocating machine including a base, a stator mounted on the base, a reciprocating assembly guided by and movable with respect to the stator, and a reservoir for liquid, the reservoir being disposed in the lower part of the machine, liquid circulating apparatus comprising a tabular device forming a chamber for the liquid, means connecting the tubular device to the reciprocating assembly and inclined with respect to the axis of movement of the reciprocating assembly, an orifice in the lower portion of the tubular device which extends into the reservoir, and a delivery orifice in the upper part of the tubular device, said delivery orifice having an area smaller than that of the remaining portion of the tubular device.

13. A method of circulating fluid in a reciprocating machine having a reciprocating assembly guided by and movable with respect to a stator comprising the steps of flowing a quantity of fluid into a chamber having a delivery orifice in the machine, utilizing the forces of inertia resulting from movement of the reciprocating assembly to set the fluid in motion with respect to the chamber and utilizing the reaction forces developed by guiding walls of the chamber to circulate the fluid towards the delivery orifice and through the orifice to another region of the machine.

References Cited UNITED STATES PATENTS 3,103,603 9/1963 Reutter 3l0l5 XR 3,058,649 10/1962 Plegat 3l018 XR 2,161,408 6/1939 Coons l03--53 2,633,327 3/1953 McDowell l0382 X R 2,944,160 7/1960 Dickinson 310-l5 XR 3,344,293 9/1967 Wahl 310- XR 2,875,989 3/1959 Toulmin 31030 XR 2,370,347 2/1945 Goebel 103-82 3,147,914 9/1964 Hatten et al 310-51 XR 2,935,629 5/1960 Chausson 31027 2,177,795 10/1939 Von Delden 3l0-30 XR FOREIGN PATENTS 1,523,129 5/ 1968 France.

WARREN E. RAY, Primary Examiner B. A. REYNOLDS, Assistant Examiner US. Cl. X.R.

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