MXPA06009651A - Long-piston hydraulic machines - Google Patents

Abstract

Smaller and lighter hydraulic pump/motors provide remarkably improved volumetric efficiency with pistons having body portions substantially as long as the axial length of the respective cylinders in which they reciprocate. A plurality of respective lubricating channels, formed circumferentially and radially transecting the walls of each cylinder, are each positioned to be almost completely closed at all times by the axial cylindrical body of each respective piston during its entire stroke. Each lubricating channel is interconnected, one to another, to form a single, continuous lubricating passageway entirely within the cylinder block and not connected by either fluid"input"or fluid"output"passageways, being replenished solely by a minimal flow of fluid entering from the valve end of each cylinder and passing between each respective cylindrical wall of each cylinder and the axial cylindrical body of each respective piston. Several embodiments are disclosed in combination with various spring-biased hold-down assemblies.

Description

LONG PISTON HYDRAULIC MACHINES BACKGROUND OF THE INVENTION FIELD OF THE INVENTION This invention relates to hydraulic fluid pump / motor machines suitable for relatively heavy-duty automotive use, eg, for hydraulic transmissions used for locomotion of vehicles and / or for the storage and recovery of fluids in energy saving accumulator systems. [Note: the term "liquid" is used to distinguish it from "gas" hydraulic pumps, e.g., pumps for compressing air and / or other gases. DESCRIPTION OF THE RELATED ART Pumps and hydraulic motors are well known and widely used, having reciprocating pistons installed in respective cylinders formed in a cylinder block and positioned circumferentially at a first radial distance about the rotational axis of a drive element. Many of these pump / motor machines have variable displacement capabilities and are generally of two basic designs: (a) either the pistons alternate in a cylinder block against a drive plate variably inclined or otherwise fixed; or (b) the pistons alternate in a fixed cylinder block against a variably tilted and rotating drive plate that is frequently displaced to include a non-rotating "swing plate" (ie, just a nutator) that slides over the surface of a rotating rotor and nutator. Although the present invention is applicable to both designs, it is particularly suitable for, and is described herein as, an improvement on the last type of machine in which the pistons alternate in a fixed cylinder block. As indicated above, this invention is directed to liquid type hydraulic machines (as distinguished from "gas") and the terms "fluid (s)" and "pressurized fluid (s)" should be understood, as used herein throughout the specification and claims, they aim to identify non-compressible liquids instead of compressible gases. Due to the non-compressibility of the liquids, the pressure and load operation cycles of these two different types of hydraulic machines are so radically different that the designs for the gas compression type machines are unsuitable for use in the machines of liquid type, and vice versa. Accordingly, it should be understood that the following annotations are directed and applicable to liquid type hydraulic machines and primarily to heavy duty automotive applications such as those identified in the previous section of Technical Field. Hydraulic machines with fixed cylinder blocks can be constructed much lighter and smaller than the machines they must support and protect high-rotation cylinder blocks. However, these lighter machines require rotating and nutating plate motors that are difficult to install and support. For high-pressure / high-speed service, the drive plate installation must be supported in a manner that allows relative movement between the non-rotating piston heads and an equivalent surface of the rotating and driving plate. As indicated above, such prior art drive plates have often been divided into a rotational / nutating rotor portion and a single-running oscillating plate portion, the latter including the flat surface that equals the non-rotating piston heads through "bolts" connection. That is, such fixed cylinder block machines have hitherto used a "bolt" extension rod (ie, a rod with two spherical ends) to interconnect one end of each piston with the flat surface of the oscillating plate but not rotary A spherical end of the bolt is pivotally installed on the head end of the piston, while the other spherical end is commonly covered by a pivotally installed conventional "footing" element which must be held all the time in full and flat contact against the flat surface of the drive plate during all relative movements between the heads of the non-rotating pistons and an equivalent flat surface of the driving plate. As is well known in the art, these relative movements follow noncircular variable trajectories that occur in all the inclinations of the motor plate far from 0o. These bolts greatly increase the complexity and cost of construction of the rotating drive plates of these lighter machines. Bolt rods are also sometimes used to interconnect one end of each piston with the tilted (but non-rotating) drive plates of hydraulic machines with rotating cylinder blocks. However, more often this type of machine omits such bolts, using elongate pistons instead, each having a spherical head at one end (again, commonly covered by a conventionally installed pivot shoe element) that effectively contacts the non-rotating flat surface of the drive plate. Such elongated pistons are designed so that a significant portion of the axial cylindrical body of each piston remains supported by the walls of its respective cylinder at all times even during the maximum shock of the piston. This additional support of such elongated pistons is designed to ensure a minimum lateral displacement of each spherical piston head while slipping on the tilted but not rotating drive plate when the pistons rotate with their cylinder block. Generally, these elongated pistons are lubricated primarily by "gas passage", ie, that portion of the high pressure fluid that is driven between the walls of each cylinder and the outer circumference of each piston body while the reciprocating piston is driven or It is driven by high pressure fluid. Such a gas passage provides good lubrication only if tolerances allow sufficient fluid flow between the cylinder walls and the long piston cylinder body, and sufficient gas passage to ensure good lubrication frequently negatively affects the volumetric efficiency of the piston. pump or motor machine. For example, a 10-cubic-inch machine can use as much as 4 gallons of fluid per minute for gas passage. Although the smallest intolerances can commonly be used to reduce the passage of gas, the reduction of such tolerances is limited by the need for adequate lubrication which increases with the dimension of the pressure and the operating loads of the machine. Of course, such gas passage is achieved using fluid that would otherwise be used to drive or be driven by the pistons to achieve function. Consequently, in the example given above, the 4 gallons of fluid per minute used for gas passage lubrication, reduce the volumetric efficiency of the machine. The invention described below is aimed at improving the volumetric efficiency of such elongated piston machines while, at the same time, ensuring (a) the proper lubrication of the pistons and (b) simplifying the apparatus used to maintain contact between the pistons. and the drive plate. SUMMARY OF THE INVENTION The invention is described in various embodiments of hydraulic machines, all of which share a new combination of simple structural features including elongated pistons that alternate in a fixed cylinder block, cylinders provided with unique lubrication openings, and brake shoes directly attached to each piston(without bolts) that make sliding contact with a rotating and pointing motor plate or, preferably, with the oscillating plate portion only of a split motor plate. These simple structural characteristics, synergistically result in (a) a marked increase of 90% in volumetric efficiency and (b) such an increase in mechanical efficiency that even the drive shafts of machines as large as 12 cubic inches of capacity they can be easily rotated manually when the machine is fully assembled. Each described machine can operate either as a pump or as an engine. One embodiment has a drive plate which, while rotating at all times with the drive element of the machine, is fixed at a predetermined inclined angle relative to the axis of the drive element so that the pistons move at a predetermined maximum shock in every moment The drive plates of the other machines described have slopes that can vary along a range of angles in a manner well known in the art to control the impact of the pistons along a range of movements up to a maximum in each address. [However, those skilled in the art will appreciate that the invention is equally applicable to hydraulic machines with rotating cylinder blocks and drive plates that do not rotate with the drive elements of the machines]. In each machine, according to the invention, each piston is elongated, having an axially cylindrical body portion which is preferably substantially as long as the axial length of the respective cylinder in which they alternate. Preferably, each piston also has a spherical head end which, by means of a conventional pivot shoe and a relatively simple apparatus, is maintained in effective sliding contact with a flat surface of the motor plate of the machine. The axial length of each cylindrical piston body is selected to ensure a minimum lateral displacement of the first spherical end of the piston at all times. Accordingly, the preferred piston for this invention is "elongated". That is, even when each piston extends to its maximum shock, that portion of the piston body that is still supported within its respective cylindrical is sufficient to ensure a minimum lateral displacement of the extended spherical end of the piston at all times during the operation of the machine. [NOTE: to facilitate the explanation of the invention, each piston is described having a cylindrical axial body portion and a spherical head end, while each respective cylinder has a valve end and an open head portion beyond which The spherical head end of each piston extends at all times. Furthermore, for all preferred embodiments, it is assumed that each hydraulic machine described (e.g., either motor or pump) is paired with a similar hydraulic machine. (e.g., a pump or equivalent motor) in a well-known "closed cycle" arrangement (see Figure 10) wherein the high pressure fluid exiting from outlet 139 of each pump 110 is supplied directly to the inlet 36 of the related motor 10, while the low pressure fluid leaving the outlet 37 of each motor 10 is supplied directly to the inlet 136 of the related pump 110. As understood in the art, a portion of the fluid in this closed cycle system is continuously lost to the "gas passage" and collected in a lubricant collector; and the fluid is automatically supplied from the manifold back to the closed cycle, by means of a charge pump, to maintain a predetermined volume of fluid in the closed cycle system at all times]. According to the invention, each cylinder formed within the cylinder blocks of each machine is provided with a respective lubricant channel formed in the cylindrical wall of each cylinder. This lubricant channel is placed so that all the time during the reciprocation of the piston inside its respective cylinder, each respective lubricant channel remains almost completely closed by the axial cylindrical body of the piston during its complete collision. [The movement of fluid in these lubricating channels is discussed in more detail beginning two paragraphs below]. Preferably, each respective lubricant channel is circumferentially formed and radially transects each cylinder. Also formed in the fixed cylinder block of each machine is a plurality of additional passages interconnecting each of the newly described lubricating channels. The interconnection of all lubricating channels together forms a single continuous lubricant passage in the cylinder block. This continuous lubricant passage is completely formed within the cylinder block, preferably by transecting each cylinder and centering circumferentially at substantially the same distance as the cylinders are centered around the rotational axis of the drive member. Special attention is paid to the fact that, in the preferred embodiments described, the continuous lubricant passage just described above, is not connected by "inlet" or "outlet" fluid passages but is almost closed by the body portions cylindrical pistons at all times during the operation of the machine. Accordingly, the only source of lubricating fluid that supplies this continuous lubricant passage is a minimum secondary flow of fluid between each of the respective cylinder walls of each cylinder and the axial cylindrical body of each respective piston. During operation, this lubricant passage is filled almost instantaneously with a minimum initial flow of high pressure fluid that enters the end of the valve of each cylinder and then passes between the walls of each cylinder and the outer circumference of the body portion of each piston driven. This minimum secondary flow effectively maintains the high pressure within the continuous lubricant passage at all times. If necessary, a plurality of sealing members each located respectively near the open end of each cylinder, can provide a relatively hermetic seal to substantially eliminate the passage of gas between the body portion of each piston and the open head portion of the piston. each respective cylinder, thus allowing the escape of only a minimum passage of gas from this lubricant passage to the open end of the cylinders. However, in actual practice, it has been found that only a relatively minimal gas passage from the open end of the cylinders moves past the elongated pistons of the invention, and, since a small amount of fog of Gas passage for proper lubrication of the bearings of the drive shaft, etc., such optional sealing members may not be necessary. However, the lubricating fluid in this continuous lubricant passage constantly moves as a result of the changing pressures in each of the respective cylinders while the pistons alternate. That is, since the pressure in each cylinder is reduced at low pressure in the return stroke of each piston, the high-pressure fluid in the otherwise closed lubricant passage is actuated again between the walls of each cylinder and the External circumference of the body of each piston at the valve end of each cylinder undergoing such pressure reduction. However, the lubricating fluid that is operated at low pressure is not "lost", i.e., is not "gas passage" and does not return to the manifold to be filled in the closed-cycle hydraulic system by means of the charge pump. Conversely, this low pressure lubricating fluid is immediately returned to the closed cycles without requiring the use of a charge pump, and the closed continuous lubricant passage is immediately filled by the inlet of a similar flow of high pressure end fluid. of the valve of each cylinder that experiences an increase in pressure. The lubricant passage just described provides proper lubrication for high-speed reciprocation of the pistons while substantially reducing the passage of gas. During the successful operation of commercial prototypes constructed in accordance with the invention, the gas passage was reduced by 90%. That is, the gas passage experienced by conventional commercial hydraulic machines of comparable specifications generally varies between 4-5 gallons per minute, while the gas passage experienced by the prototypes of the invention varies between 0.5-0.7 gallons per minute, increasing markedly the volumetric efficiency of the hydraulic machines of the invention.

As indicated above, fixed cylinder block hydraulic machines can be constructed smaller and lighter than conventional rotary block hydraulic machines that have similar specifications. As a result of the improved lubrication of the elongated pistons, the invention described makes it possible to use smaller and lighter designs to meet the high speed / high pressure specifications required for automotive use. In addition, special attention is given to the significantly simplified support facilities of the invention for the variable rotary drive plates of the described hydraulic machines of the invention. All of the support installations of the invention described herein omit the bolts that are normally installed between the outer end of each piston and the only swinging plate portion of a conventional rotating / nutancing drive plate. In addition, one embodiment also omits the only remaining oscillating plate portion of a conventional rotating / nutating drive plate. In all embodiments, a conventional shoe is installed directly to a spherical head of each piston and is maintained in effective sliding contact with the flat surface portion of the drive plate by means of a minimum spring deflection sufficient to maintain such effective contact of sliding in the absence of hydraulic pressure at the ends of the valve of the cylinders of the pump. Three simplified support mechanisms are described. The first simplified support mechanism comprises a single mounting plate arrangement inclined by a single spring positioned circumferentially around the rotational axis of the pump drive element. The second support mechanism of the invention is even simpler, comprising nothing more than a conventional shoe installed directly to the spherical head of each piston, supplying the minimum inclination for a plurality of springs, each spring being respectively placed within the body portion of each respective piston between the body portion of each respective piston and the valve end of each respective cylinder. Although the second support mechanism is a bit more difficult to assemble than the first, the latter is considerably simpler and cheaper to manufacture. The third of the simplified support mechanisms described is the preferred arrangement. That is, it includes a separate, but modified, traditional drive plate by adding needle bearings to support the only pendulum plate portion on the rotating / rotating rotor member. Aungue this third embodiment also includes a single installation of clamping plate similar to the first embodiment, this last clamping plate is tilted by the plurality of springs, each spring being located, respectively, circumferentially on the sliding shoe with the head of each piston . This third embodiment provides a dramatic change in the operating dynamics of the sliding shoes, significantly reducing the surface speed of relative movement between the shoes and the drive plate and, consequently, resulting in a reduction in wear and cost, and a significant increase in the efficiency of the machine. The important changes introduced by this invention provide lighter and smaller hydraulic machines than conventional machines having similar specifications. In addition, as indicated above, the actual testing of working prototypes has proven that this invention provides machines with a significant increase in volumetric and mechanical efficiency. Briefly, the invention described herein provides machines that have a markedly higher efficiency while significantly reducing the weight and size of the machines as well as the cost of manufacturing and simplifying the installation. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a partial schematic and cross-sectional view of a hydraulic machine with a fixed cylinder block and a rotating / nutating drive plate having a fixed angle of inclination, showing the characteristics of the invention incorporated in the cylinder block and in the piston / drive plate interface. Figure 2 is a partial schematic and cross-sectional view of the fixed cylinder block of the hydraulic machine of Figure 1 taken along the plane 2-2 omitting parts for clarity. Figure 3 is a partial and cross-sectional schematic view of a hydraulic machine with a fixed cylinder block and a rotating / nutating motor plate having a variable angle of inclination, again showing the characteristics of the invention incorporated in the block of cylinders and in the piston / drive plate interface. Figures 4A and 4B are partial and cross sectional schematic views of the drive plate and piston shoe fastening installation described in Figures 1 and 3, with parts removed for clarity, showing the relative positions of the head ends of the piston shoes. pistons, shoes and special cleaners, as well as the spring-biased clamping element that tilts each sliding shoe against the flat face of the drive plate when the drive plate is tilted at 125 °, taking the view in Figure 4A in the plane 4A-4A of Figure 3 in the direction of the arrows, while the view in Figure 4B is taken in the plane 4B-4B of Figure 4A. Figures 5A and 5B, 6A and 6B and 7A and 7B are views of the same parts illustrated in Figures 4A and 4B, when the drive plate is inclined, respectively, at 15 °, 0 ° and 25 °, taking the respective views in Figures 5B, 6B and 7B in the respective planes 5B-5B, 6B-6B and 7B-7B of Figures 5A, 6A and 7A. Figure 8 is an enlarged, partial, schematic and cross-sectional view of a single cylinder and piston for another hydraulic machine similar to those shown in Figures 1 and 3 but showing a second, more simplified embodiment of a spring-biased fastening installation for the piston shoes of the invention. Figure 9 is a partial and cross-sectional schematic view of another embodiment of the invention, showing a portion of another hydraulic machine with a fixed cylinder block substantially identical to that described in Figure 3, but including an improved version of a drive plate Conventionally divided with a variable angle of inclination and having a single-tiered oscillating plate installed in a rotating / nutating rotor, this view omitting the valve end of the cylinder block and housing portions as well as other parts for clarity. Figure 10 is a view of a "closed cycle" installation of the prior art of two hydraulic machines. DETAILED DESCRIPTION OF THE INVENTION The operation of hydraulic machines of the type to which the invention may be added is well known. Consequently, such an operation will not be described in detail. As indicated above, it can be assumed that each described machine is connected in a well-known "closed cycle" hydraulic system with an appropriately equivalent pump or motor. Hydraulic Motor With reference to Figure 1, the hydraulic motor 10 includes a fixed cylinder block 12 having a plurality of cylinders 14 (only one shown) in which a respective plurality of equivalent pistons 16 alternate between the retracted position of the piston 16 and the extended piston position 16 '. Each piston has a spherical head 18 installed in a neck 20 at one end of an elongated axial cylindrical body portion 22 which, in the preferred embodiment shown, is substantially as long as the length of each respective cylinder 14. Each spherical end 18 is it fits inside a respective shoe 24 which slides on a flat face 26 formed on the face of a rotor 28 which, in turn, is fixed to a drive element, ie the axis 30 of the machine.

The shaft 30 is supported in bearings within a hole 31 in the center of the cylinder block 12. The flat face 26 of the rotor 28 is inclined at a predetermined maximum angle (eg, 25 °) towards the axis 32 of the drive shaft 30. A modular valve assembly 33, interlocked as a cap on the left end of the cylinder block 12, includes a plurality of discharge valves (only one shown) that regulate the supply of fluid in and out of the cylinders 14. As As indicated above, each of the described machines can be operated either as a pump or as an engine. For this description of a preferred embodiment, the fixed-angle drive plate machine shown in Figure 1 is operated as a motor. Accordingly, during the first half of each revolution of the drive shaft 30, the high pressure fluid from the inlet 36 enters the valve end of each respective cylinder 14 through a port 37 to drive each respective piston from its retracted position to its fully extended position; and during the second half of each revolution, the low pressure fluid is discharged from each respective cylinder through the port 37 and the fluid outlet 39 while each piston returns to its fully retracted position. In a manner well known in the art, the fluid inlet 36 and the outlet 39 are preferably connected through appropriate "closed cycle" tubing to an equivalent hydraulic pump so that at all times, the fluid pressure tips the spherical ends 18 and the respective shoes 24 against the flat face 26. The extension and retraction in series of each respective piston causes the rotor 28 to rotate, consequently the driver shaft 30. Also, as is well known in the art, the motor 10 is connected in a closed cycle of circulating hydraulic fluid with an equivalent hydraulic pump (eg, the pump 110 shown in Figure 3 as discussed below), and the flat face 26 is fixed at the maximum angle of inclination so that, when the flow rate of the hydraulic fluid circulating in the closed cycle through the inlet 36 and the outlet 39 is relatively small, the pistons 16 alternate relatively slower, resulting in a relatively slow rotation of the drive shaft 30. However, while increasing the flow relationships of the fluid circulation in the closed cycle, the reciprocation of the pistons increases accordingly, and thus the rotation speed of the driving shaft is increased. When operating at automotive speeds or pressures (eg, up to 400 rpm p 4000 psi), the lubrication of the pistons becomes critical and can also greatly increase gas passage losses. The cylinder block 12 is modified by the invention to meet such lubrication needs and to reduce such gas passage losses. Referring now to Figures 1 and 2, the cylindrical wall of each cylinder 14 is radially transected by a respective lubricant channel 40 formed circumferentially therein. A plurality of passages 42 interconnects all lubricating channels 40 to form a continuous lubricant passage in the cylinder block 12. Each respective lubricant channel 40 is substantially closed by the axial cylindrical body 22 of each respective piston 16 during the total collision of each piston. That is, the outer circumference of each cylindrical body 22 acts as a wall enclosing each respective lubricating channel 40 at all times. In this way, even when the pistons 16 alternate through maximum collisions, the continuous lubricating passage interconnecting all the lubricating channels 40 remains substantially closed. The continuous lubricant passage 40, 42 is simply and economically formed within the cylinder block 12 as can best be appreciated from the schematic illustration in Figure 2 in which the relative size of the fluid channels and the connecting passages has been exaggerated for clarification. During the operation of the hydraulic motor 10, all interconnected lubricating channels 40 are filled almost instantaneously by a minimum flow of high pressure fluid from inlet 36 entering each cylinder 14 through port 37 and driven between the walls of the cylinders and the outer circumference of each piston 16 The loss of lubricating fluid from each lubricating channel 40 is restricted by a peripheral seal 44 located near the open end of each cylinder 14. However, the lubricating fluid in this continuous lubricating passage of lubricating channels 40, flows moderately but continuously as a result of a continuous minimum flow of fluid between each of the respective cylindrical walls of each cylinder and the axial cylindrical body of each respective piston in response to the movement of the piston and to the changing pressures in each half cycle of rotation of the driving shaft 30 while the pistons alternate While the pressure in each cylinder 14 is reduced at low pressure in the return stroke of each piston 16, the high pressure fluid in the otherwise closed lubricant passage 40, 42 is again conducted between the walls of each cylinder 14 and the outer circumference of the body portion 22 of each piston 16 at the valve end of each cylinder 14 undergoing such pressure reduction. However, special attention is drawn to persons skilled in the art to the fact that this recently mentioned minimum flow of fluid back to cylinder 14 is not "lost". On the contrary, it is immediately returned to the well-known closed hydraulic fluid cycle which interconnects the pump and the motor. In addition, this minimum fluid flow does not return to a manifold and, consequently, does not have to be filled in the closed-cycle hydraulic system by a charge pump. Finally, the closed continuous lubricant passages 40, 42 are immediately filled by the entry of a similar minimum flow of high pressure fluid from the end of the valve of each cylinder undergoing a pressure increase. As mentioned above, there is a minimal loss of gas passage from the continuous lubricant passage 42 which interconnects all the lubricating channels 40. That is, there is still some minimum flow of fluid leaking from this continuous lubricant passage past the seals 44 at the end of each cylinder 14. However, any minimum gas passage is instantly filled by a similar minimum flow of high pressure fluids entering around the opposite end of each piston 16. The lubrication installation just described is not only markedly simple, and allows a similar simplification of the pinion / drive plate interface of the hydraulic machine to further reduce the cost of manufacturing and operation.

To complete the description of the hydraulic motor 10, the pinion / drive plate interface apparatus shown in Figure 1 comprises only (a) the rotor 28 installed on the drive shaft 30 using conventional needle and thrust bearings and (b) a single spring-biased securing installation to keep the piston shoes 24 in constant contact with the flat surface of rotation and nutation 26 of the rotor 28. [Note: three simplified embodiments of the pinion / drive plate interface installations of the invention are described. . Although only the first of these fastening facilities is shown in combination with the motor and pump illustrated in Figures 1 and 3, each is described in more detail in separate section below]. The first embodiment of the fastening installation of the invention, as shown in Figure 1, includes a spiral spring 50 which is placed around the arrow 30 and is received in an appropriate slit 52 formed in the cylinder block 12 circumferentially around of the shaft 32. The spring 50 deflects a clamping element 54 which is also positioned circumferentially around the arrow 30 and the shaft 32. The clamped member 54 is provided with a plurality of openings, each of which surrounds the neck 20 of a respective piston 16. A respective special washer 56 is placed between the clamping element 54 and each piston shoe 24. Each washer 56 has an extension 58 that contacts the outer circumference of a respective shoe 24 to keep the shoe in contact with the flat surface 26 of the rotor 28 at all times. The hydraulic motor 10 recently described with its remarkable simplification of both lubrication and piston / drive plate interfaces, is efficient, easy to manufacture and economical to operate. Variable Hydraulic Pump A second preferred embodiment of a hydraulic machine according to the invention is illustrated in Figure 3. A variable hydraulic pump 110 includes a modular fixed cylinder block 112 which is identical to the cylinder block 12 of the hydraulic motor 10 shown in FIG. Figure 1 and described above. The cylinder block 112 has a plurality of cylinders 114 (only one is shown) in which a respective plurality of coupling pistons 116 alternate between the retracted position of the piston 116 and the variable extended positions (the maximum extension being that shown in FIG. the position of the piston 116"). Each piston has a spherical head 118 which is installed on a neck 120 at one end of a cylindrical body portion 122 of the elongated shaft which, in the embodiment shown, is substantially as long as the length of each respective cylinder 114. Each head of Spherical piston 118 fits within a respective shoe 124 which slides on a flat face 126 formed on the surface of a rotor 128 which, as will be discussed in more detail below, is pivotally attached to the actuating element, ie, the arrow 130 which is supported on the bearings within a hole in the center of the cylinder block 112. In a manner similar to that explained above with respect to the hydraulic motor 10, the variable pump 110 is also provided with a modular valve installation 133 which is screwed in as a cover on the left end of the modular cylinder block 112 and, similarly, includes a plurality of spool valves 134 (only shown) ra) regulating the supply of fluid in and out of the cylinders 114. As indicated above, each of the described machines can be operated either as a pump or as a motor. For the description of this preferred embodiment, the variable angle drive plate machine 110 shown in Figure 3 is operated as a pump and the drive shaft 130 is driven by a motor not shown, e. g. , the engine of a vehicle. Therefore, during the middle of each revolution of the drive shaft 130, the lower pressure fluid is drawn to each respective cylinder 114 that enters a port 137 from a "closed loop" of circulating hydraulic fluid through the inlet 136. as each piston 116 moves to an extended position; and during the next half of each revolution, the transmission of each respective piston 116 back to its fully retracted position directs the high pressure fluid from port 137 to the closed hydraulic cycle through outlet 139. The high pressure fluid then it is supplied through the appropriate closed cycle pipe (not shown) to a hydraulic coupling pump, e. g. , the above-discussed pump 12, which causes the pistons of the coupling pump to move at a rate that varies with the volume (gallons per minute) of the high pressure fluid that is supplied in a manner well known in the art. Once referring again to modular cylinder block 112, it is constructed identical to cylinder block 12 that has already been described. That is, the cylindrical wall of each cylinder 114 is crossed in radial cross section by a respective lubrication channel 140 formed circumferentially therein. A plurality of passages 142 interconnect all lubrication channels 140 to form a continuous lubrication passage in the cylinder block. A cross section of the cylinder block 112 taken in the plane 2-2 is viewed exactly as the cross-sectional view of the cylinder block 12 of Figure 2.

In fact, almost everything discussed above, in relation to the continuous lubrication passages 40, 42 of the invention with reference to the apparatus of the hydraulic motor 10 shown in Figures 1 and 2, applies equally to the operation of the lubrication passage. continuous 140, 142 in the cylinder block 112 of the hydraulic pump 110 shown in Figure 3, including the totally extreme minimization of the loss of lubricating fluid from each lubrication channel 140 by optionally including a surrounding seal 144 located near the open end of each cylinder 114. Similarly, the flow of the lubrication fluid in the closed continuous lubrication passage 140, 142 is moderate, but continuous as a result of a minimum secondary fluid flow in response to piston movement and pressure changing in each half rotation cycle of the driving shaft 130 as the pistons alternate. Of course, since it is different in the pump 110, the lower fluid pressure is present in each cylinder 114 when each piston 116 moves to an extended position, while the source of the high pressure fluid that is forced between the walls of the cylinders 114 Cylinders and the outer circumference of each piston 116 occur as each piston is driven from its extended position to its fully retracted position by the rotation of the driving shaft 130 by the engine (not shown).

However, once again the attention of the person skilled in the art is drawn to the fact that this aforementioned secondary minimum fluid returning to each cylinder 114 is not "lost". Rather, it returns immediately to the well-known closed hydraulic fluid cycle that interconnects the pump and the motor. That is, this secondary fluid flow does not return to a manifold and, therefore, does not have to be replenished to the closed cycle hydraulic system by a charge pump. Also, although there may be minimal leakage of gas leaking from the closed continuous lubrication passage 140, 142 beyond the seals 144 at the end of each cylinder 114, any such minimal gas leak is instantly replenished by a fluid flow. similar minimum that goes around the opposite end of each piston 116 that experiences increased pressure. As discussed in the foregoing preamble, the invention allows the machine plate apparatus to be simplified (a) by omitting the profile bars that are normally installed between the outer end of each piston and a portion of the piston rod. nutation clutch only of a conventional rotation / nutation drive plate and (b) in the embodiments illustrated in Figures 1 and 3, by omitting the clutch rod portion itself as well as the apparatus conventionally required to install the clutch rod without rotation to the rotation / nutation rotor portion of the drive plate. Referring still to Figure 3, the rotor 128 of the pump 110 is installed pivotally to the drive shaft 130 about an axis 129 that is perpendicular to the axis 132. Therefore, while the rotor 128 rotates with the drive shaft 130, its angle of inclination in relation to the axis 130 can be varied from 0o (ie perpendicular) to ± 25 °. In Figure 3, the rotor 128 is tilted to + 25 °. This variable inclination is controlled as follows: The rotation of the rotor 128 about the axis 129 is determined by the position of a sliding collar 180 that surrounds the drive shaft 130 and moves axially relative thereto. A control link 182 connects the collar 180 with the rotor 128 so that the movement of the collar 180 axially on the surface of the drive shaft 130 causes the rotor 128 to rotate about the shaft 129. For example, as the collar 128 is moves to the right in Figure 3, the inclination of the rotor 128 varies across a whole continuous spectrum from the inclination of + 25 ° shown, back to 0 ° (ie perpendicular), and then up to -25 °. The axial movement of the collar 180 is controlled by the fingers 184 of a fork 186 as the fork 186 is rotated about the axis of a fork rod 190 by the articulation of a fork control arm 188. The fork 186 is actuated. by a conventional linear servo-mechanism (not shown) connected to the lower part of the fork arm 188. In this preferred embodiment, although the rest of the elements of the fork 186 are all included within a modular motor-plate housing 192 and the fork bar 190 is supported in bearings fixed to the housing 192, the fork control arm 188 is positioned external to the housing 192. It will also be noted that the rotor 128 of the drive plate is swung by a shadow link 194 which is substantially identical to the control link 182 and is connected similarly to the collar 180 but in a location on exactly the opposite side of the collar 180. s Piston Pad Clamping The fluid pressure constantly deflects the pistons 116 in the direction of the rotor 128, and the illustrated conventional pulse plate installation is provided to carry that load. However, at the operating speeds required for automotive use (e.g., 4000 rpm) the additional deflection load is necessary to ensure constant contact between the piston shoes 124 and the flat surface 126 of the rotor 128. In view from the omission of the invention of conventional profiled bars, the variable hydraulic machines of this invention provide such additional deviation by using one of three simple spring-biased fastening systems, the first being similar to that already briefly described above with respect to the motor Hydraulic 10 in Figure 1. (a) Installation of Clamping with Deviation by Single Spring The following description of the first embodiment of the invention for a continuous fastening installation when referring to Figure 3, but reference is now also made to (a) to Figure 4A which shows an enlarged view taken in the plane 4A-4A of Figure 3 when viewed in the direction of the arrows, and (b) to Figure 4B showing an enlargement of the same view shown in Figure 1 with parts removed for clarity. . The clamping device for the pump 110 includes a coil spring 150 which is placed around the rod 130 and is received in an appropriate groove 152 formed in the cylinder block 112 circumferentially around the shaft 132. The coil spring 150 deflects a clamping element 154 which is also positioned circumferentially around the bar 130 and the shaft 132. The clamping element 154 is provided with a plurality of circular openings 160, each of which surrounds the neck 120 of a respective piston 116. A plurality of special washers 156 are placed, respectively, between the clamping element 154 and each piston shoe 124. Each washer 156 has an extension 158 that contacts the outer circumference of a respective shoe 124 to maintain the shoe in contact with the flat face 126 of the rotor 128 at all times. The positions of the already described parts of the fastening device of the drive plate and the piston shoe change in relation to each other as the inclinations of the rotor 128 are altered during the operation of the machine. These changes in the relative position are illustrated in various inclinations of the rotor 128, that is, a, + 25 °, in Figures 4A and 4B; a + 15 ° in Figures 5A and 5B; at 0o in Figures 6A and 6B; and at -25 °, in Figures 7A and 7B. [Note: Those skilled in the art will appreciate that each piston shoe 124 has a conventional pressure balance cavity centered on the flat surface of the shoe 124 that connects the flat face 126 of the rotor 128 and that of each respective shoe cavity. it is connected through an appropriate shoe channel 126 and the piston channel 164 to ensure that the fluid pressure present at the shoe / rotor interface is equivalent at all times with the fluid pressure at the head of each piston 116. that the piston channel 164 passes through the center of the spherical head 118 of each piston 116, the position of the channel 164 can be used to facilitate the appreciation of the relative movements of the various parts of the fastening installation. Referring to the relative position of these parts in the 0 ° inclination shown in Figures 6A and 6B, each piston channel 164 (in the center of each spherical head 118 of each piston 116) has the same radial position in relation to each respective circular opening 160 in the fastener 154. As can be seen from the views in the other illustrated inclinations of the drive plate rotor 128, in all inclinations other than 0 °, the relative radial position of each piston channel 164 it is different from each opening 160 and the relative positions of each special washer 156 is also different. It should be appreciated that, in each of these inclinations of the driving plate illustrated, the different relative positions in each of the nine openings 160 are themselves constantly changing as the rotor 128 rotates and rotates through a full revolution in each one of these inclinations. For example, in the inclination of 25 ° shown in Figure 4A, if during each revolution of the rotor 128, the movement occurring through only the opening 160 in the upper part (i.e., at 12:00 hours) was observed. ) of the fastening element 154, relative position of the parts observed in the upper aperture 160 would serially change to equal the relative positions shown in each of the other eight apertures 160. That is, at inclinations other than 0 ° (eg g. , at -25 ° shown in Figure 7A) during each revolution of the rotor 128, each special washer 156 slides on the surface of the fastening element 154 while, simultaneously, each shoe 124 slides on the flat face 126 of the rotor 128.; and each of these parts changes in relation to its own opening 160 through each of the various positions that can be observed in each of the other eight openings 160. These relative movements are the largest at ± 25 ° and each follows a cyclic trajectory (which seems to trace a lemniscate ie "figure of eight" which varies in size with the angular inclinations of the drive plate rotor 128 and the horizontal position of each piston 116 in the fixed cylinder block 112. Therefore, to ensure proper contact between each respective shoe 124 and the flat surface 126 of the rotor 128 in the preferred embodiments a size is selected for the boundaries of each opening 160 so that the edges of the opening 160 remain in contact with more than one half of the surface of each special washer 156 at all times during each revolution of the rotor 128 and during all the inclinations of the rotor 128, as can be seen from of the relative positions of the special washers 156 and the edges of each of the openings 160 in each of the drawings of Figure 4A to Figure 7A. As can be seen from the drawings, a circular edge is preferred for each opening 160. (b) Multi-Fastening Installation Spring Deviations of the Piston The second embodiment of the fastening installation of the invention, although slightly more difficult to assemble, is considerably simpler and less expensive. This second embodiment is shown schematically in Figure 8 in an enlarged, partial and cross-sectional view of a single piston of an additional hydraulic machine 210 according to the invention. The piston 216 is placed in the modular fixed cylinder block 212 within the cylinder 214, the latter being radially crossed in cross-section by a respective lubrication channel 40"circumferentially formed therein." In the same manner as described in connection with the other hydraulic machines already described above, each lubrication channel 40"is interconnected with similar channels in the other cylinders of the machines to form a continuous lubrication passage in the cylinder block 212 and, similarly an optional surrounding seal 44" it can be located near the open end of each cylinder 214 to further minimize the loss of lubricating fluid from each lubrication channel 40". The only difference between the fixed cylinder block 212 and the modular cylinder blocks described in Figures 1 and 3 is that the fixed cylinder block 212 does not include a large axially circumferential spiral spring or an axially circumferential groove for clamping the same. Although not shown, the modular fixed cylinder block 212 of the hydraulic machine 210 can be connected to either a fixed-angle modular drive plate installation. (as shown in Figure 1) or a modular installation of variable angle drive plate (as shown in Figure 3) but in any case, the hydraulic machine 210 provides a much simpler fastening installation. That is, the clamping installation of this embodiment comprises only one respective conventional piston shoe 224 for each piston 216 in combination with only one respective coil spring 250, the latter also being associated with each respective piston 216. Each piston shoe 224 It is similar to the conventional shoes shown in the first fastening installation already discussed above and, similarly, is installed on the spherical head 218 of the piston 216 to slide on the flat face 226 formed on the surface of the motor plate rotor 228. the machine in a similar way to the one explained above. Each coil spring 250 sits, respectively, circumferentially around the hydraulic valve port 237 at the valve end of each respective cylinder 214 and is tioned within the body portion of each respective piston 216. Again, in In the manner already explained above, each shoe 224 slides on the flat face 226 of the rotor 228 with lemniscate movement that varies in size with the horizontal tion of each piston 216 and the inclination of the rotor 228 in relation to the axis 230. During the operation Normal of the hydraulic machine 210, the shoes 224 are kept in contact with the flat face 226 of the drive plate by hydraulic pressure. Therefore, the spring deflection provided by the coil springs 250 is only minimal but still sufficient to maintain effective sliding contact between each shoe 224 and the flat face 226 in the absence of hydraulic pressure at the valve end of each cylinder. respective 214. It has been found that the minimum deviation already described of the spring 250 not only facilitates the installation but is also sufficient to prevent entrapment of small dirt and metal debris found during installation and caused by use. In addition, special attention is called again to the fact that this second modality provides this necessary function with only a few very economical parts. (c) Bracket Installation with Multiple Deviations by Shoe Spring Referring to Figure 9, a preferred fastening installation is described in a preferred hydraulic machine, ie, the pump 310 which, while substantially similar to the pump 110 illustrated in FIG. 3 and described in detail above, includes an improved conventional split motor plate installation . As with the other hydraulic machines described above, a plurality of pistons 316, each including a respective slide shoe 324 alternates in respective cylinders 314 formed in a cylinder block 312 that is identical to cylinder block 12 and 112 as described above. Each shoe 324 slides on the flat face 326 formed on a clutch rod 327 which is installed in a coupling rotor 328 by means of appropriate needle bearings 372, 374 which allow the clutch rod 327 to be numbered without rotation while the rotor 328 is both aligned. as it rotates in the manner well known in the art. It will be apparent to those skilled in the art that the inclination of the clutch rod 327 and the rotor 328 about the shaft 329 is controlled by the position of a sliding collar 380, a control link 382 and a shadow shadow link 394 exactly in same as that described above with respect to the pump 110 illustrated in Figure 3. The shoes 324 are held by a fastening system substantially identical to the first fastening installation described in detail in sub-section (a) above. . However, in this preferred embodiment, the large single spiral spring 150 is replaced by a plurality of smaller spiral springs as follows: A fastening plate 354 is fixed to a clutch rod 327 and is otherwise identical to the element of clamping 154 described in detail above with reference to the • Figures 4-7. Similarly, each shoe 324 receives the circumferential extension of a respective special washer 356 that is identical to each special washer 156 as described in detail above, and the neck of each piston 316 is positioned within a corresponding plurality of respective openings 360. formed through the holding plate 354, all exactly similar to the apparatus of the first fastening installation described in detail in sub-section (a) above. Although the clutch rod 327 does not rotate with the rotor 328, the nutational movement of the clutch rod 327 is identical to the nutational movement of the rotor 328 and, therefore, the relative movements between the shoes 324 and the flat surface 326 of the piston rod 327. clutch 327 are also identical to those described in detail in sub-section (a) above. In this embodiment, a plurality of springs in individual coils 350 provide the minimum spring deflection which is necessary, in the absence of the hydraulic pressure at the valve end of each cylinder 314, to maintain effective sliding contact between each shoe 324 and the flat face 326 of the clutch rod 327. Each coil spring 350 is positioned circumferentially around each shoe 324, being captured between each special washer 256 and a collar formed just above the bottom of each shoe 324. The preferred embodiment that already it has been described provides the same remarkable improvement in volumetric efficiency with total lubrication as the other described modalities. In addition, a dramatic change in the dynamics of sliding shoe operation is also provided, greatly improving efficiency and significantly reducing wear and associated costs associated with such wear. The hydraulic machines of the invention provide all remarkably improved volumetric efficiencies with effective lubrication as well as piston / drive plate interface installations that provide additional savings by being relatively simple and economical to manufacture and by reducing the number of parts for efficient operation. According to the foregoing, it is to be understood that the embodiments of the invention described herein are only illustrative of the application of the principles of the invention. The reference herein to the details of the illustrated embodiments is not intended to limit the scope of the claims, which themselves cite the characteristics considered essential for the invention.

Claims (6)

1. In a hydraulic machine having a plurality of pistons installed alternately in respective cylinders formed in a block of cylinders fixed in a housing and circumferentially placed at a first radial distance about the axis of rotation of a drive element, having each said piston a body portion and a head end connected to said body portion, each respective cylinder having a valve end and an open head portion, a divided motor plate driven by said actuating element and having a variably inclined rotor rotating and ñuta and a clutch rod that only ñuta, and said piston also having a stroke that varies according to the inclination of said drive plate to a predetermined maximum, comprising the improvement: a flat face located on said clutch rod; said head end of each said spherical piston being connected to said body portion by a narrow neck portion and extending at all times beyond said head end of said respective cylinder; said body portion of each piston having an elongated axial cylindrical length sufficient to be supported within said respective cylinder to ensure the minimum lateral displacement of said head end of said piston when said shoe is in sliding relative contact with said flat face in all moment during said race; a respective pivotal sliding shoe and directly fixed to said spherical head end of each said piston without any intermediate profile bar; each said sliding shoe being held in direct sliding contact with said flat face of said clutch rod during all relative rotational movements between said piston and said flat face; and a clamping device for deflecting each of said sliding shoes to said flat face of said clutch rod and comprising: a clamping element having a plurality of respective openings, the limit of each said respective opening being said holding plate located in proximity to said narrow neck portion of each respective piston; and a respective washer fitted around said narrow neck portion of each piston between said clamping plate and each respective sliding shoe, each said washer having an extension cylindrically aligned for circumferential contact with each respective sliding shoe; said washers being in sliding contact with said clamping plate for relative movement therein in response to the changing relative positions of said sliding shoe when said flat face of said rotor is inclined in relation to said rotational axis of the actuation element. The hydraulic machine of claim 1 wherein said divided drive plate further comprises roller bearings for supporting said nutation-only clutch rod on said rotating and nutating rotor. The hydraulic machine of claim 1 wherein the limit of each said respective opening in said clamping plate is designed to be in contact with more than half of the outer circumference of said respective washer at all times during said relative movements . The hydraulic machine of claim 3 wherein said machine further comprises a minimum spring deflection sufficient to maintain said effective sliding contact between said respective shoe and said flat face of said drive plate in the absence of the hydraulic pressure at said end of each respective cylinder. The hydraulic machine of claim 4 wherein said minimum spring deflection is provided by a plurality of springs, each said spring being positioned respectively between said fastening plate and one of said respective washers. The hydraulic machine of claim 4 wherein said minimum spring deflection is provided by a plurality of springs, each said spring being positioned respectively between said body portion of each respective piston and said valve end of each respective cylinder.