EP0276680A2 - Two-speed valve in-star motor - Google Patents
Two-speed valve in-star motor Download PDFInfo
- Publication number
- EP0276680A2 EP0276680A2 EP88100323A EP88100323A EP0276680A2 EP 0276680 A2 EP0276680 A2 EP 0276680A2 EP 88100323 A EP88100323 A EP 88100323A EP 88100323 A EP88100323 A EP 88100323A EP 0276680 A2 EP0276680 A2 EP 0276680A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- fluid
- fluid pressure
- star
- pressure chamber
- rotary
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C14/00—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations
- F04C14/08—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by varying the rotational speed
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C2/00—Rotary-piston machines or pumps
- F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
- F04C2/10—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member
- F04C2/103—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member one member having simultaneously a rotational movement about its own axis and an orbital movement
- F04C2/105—Details concerning timing or distribution valves
Definitions
- the present invention relates to rotary fluid pressure devices, and more particularly, to such devices which include gerotor displacement mechanisms utilizing low-speed, commutating valving.
- valve-in-star a gerotor motor in which a portion of the gerotor star itself comprises the rotary valve member
- a valve-in-star design should substantially eliminate valve timing errors because of the fixed relationship between the star and the rotary valve ports.
- U. S. Patent No. 3,825,376 illustrates one fairly early attempt at a valve-in-star design.
- each of the rotary ports associated with the gerotor star opened directly into the volume chamber, thus interrupting the star profile, which has long been recognized as being undesirable.
- U. S. Patent No. 4,411,606 A more recent attempt to provide a satisfactory valve-in-star gerotor motor is illustrated in U. S. Patent No. 4,411,606, in which the "manifold valving" or directional valving occurs between the star and the endcap, while the commutating valving occurs at the axially opposite end face of the star, at the interface of the star and an adjacent valve plate.
- Such an arrangement effectively requires that the valving be "fixed clearance", as opposed to being pressure balanced or pressure overbalanced.
- the arrangement in U. S. 4,411,606 requires a plurality of axial bores extending through the star to communicate between the opposite ends of the star.
- Low-speed, high-torque gerotor motors of the type to which this invention relates have typically been utilized in systems in which the relief valve would be set at approximately 3,500 psi, and in which the motor would operate at approximately 3,000 psi. More recently, there has been increasing demand in the marketplace for motors capable of operating at relatively high pressures, at least intermittently, in systems in which the relief valve may be set as high as 4,500 psi or even 5,000 psi.
- valve-in-star motor shown in above-cited 3,825,376, the variation in the number of volume chambers communicating with the ports, and the resulting torque ripple, make the motor shown therein unsuitable for high-pressure applications.
- two-speed means that for any given rate of fluid flow into the motor, it is possible to select between two different motor output speeds; a high-speed (low-torque), and the conventional low-speed (high-torque).
- U. S. Patent No. 3,778,198 discloses the basic concept for achieving two-speed operation of a gerotor motor.
- the motor shown in the reference patent is of the spool valve type which has been limited to relatively lower pressures and torques, because of the fixed diametral clearance between the rotating spool valve and the adjacent cylindrical housing surface.
- U. S. Patent No. 4,480,971 assigned to the assignee of the present invention, teaches a two-speed gerotor motor of the disk valve type which, therefore, is more suited for applications requiring relatively higher pressures and torques.
- the device shown in U. S. 4,480,971 will result in a commercially successful two-speed gerotor motor, the design disclosed therein is somewhat large and complex, and is subject to the pressure and torque limitations inherent in disk valve gerotor motors.
- the device comprises a housing means including an endcap member defining a fluid inlet port and a fluid outlet port; a gerotor gear set associated with said housing means and including an internally-toothed ring member and an externally-toothed star member eccentrically disposed within the ring member; either the ring member or the star member has orbital movement relative to the other of the members, and the star member has rotational movement relative to the ring member and the housing means; the internal teeth of the ring member and the external teeth of the star interengage to define a plurality N + 1 of expanding and contracting fluid volume chambers during the relative orbital and rotational movements; the device includes a shaft means and means operable to transmit the rotational movement of the star member to the shaft means; the endcap member defines a first fluid pressure chamber in continuous communication with either the inlet or outlet
- the improved device is characterized by: (a) the end surface of the star member is in sliding, sealing engagement with an adjacent surface of the endcap member; (b) the endcap member defines a third fluid pressure chamber and a control fluid passage in communication with the third fluid pressure chamber; (c) the star member defines a third manifold zone in continuous fluid communication with the third fluid pressure chamber; (d) the end surface of the star member defines a third set of fluid ports in continuous fluid communication with the third manifold zone; (e) the adjacent surface of the endcap member defines a plurality N + 1 of valve passages, each of the valve passages being in continuous fluid communication with one of the expanding and contracting fluid volume chambers; (f) the first, second and third sets of fluid ports are in commutating fluid communication with the plurality N + 1 of valve passages, defined by the endcap member, in response to the relative rotational movement of the star member; and (g) a valve means is selectively operable between a first condition communicating the control fluid passage to the first fluid pressure chamber, and
- FIG. 1 illustrates a low-speed, high-torque gerotor motor.
- the hydraulic motor shown in FIG. 1 comprises a plurality of sections secured together, such as by a plurality of bolts 11.
- the sections of the motor include a shaft housing portion 13, a gerotor displacement mechanism 15, and an endcap member 17.
- the gerotor displacement mechanism 15 (best seen in FIG. 3) is well known in the art, is shown and described in great detail in U. S. Patent No. 4,343,600, which is assigned to the assignee of the present invention, is incorporated herein by reference, and therefore will be described only briefly herein. More specifically, the displacement mechanism 15 is a Geroler® gear set comprising an internally-toothed ring member 19 defining a plurality of generally semi-cylindrical openings, with a cylindrical roller member 21 disposed in each of the openings, and serving as the internal teeth of the ring member 19.
- Eccentrically disposed within the ring 19 is an externally-toothed star 23, typically having one less external tooth than the number of internal teeth 21, thus permitting the star 23 to orbit and rotate relative to the ring member 19.
- the relative orbital and rotational movement between the ring 19 and the star 23 defines a plurality of expanding fluid volume chambers 25 and a plurality of contracting fluid volume chambers 27, as is well known in the art.
- the star 23 defines a plurality of straight, internal splines 29, which are in engagement with a set of external crowned splines 31 formed on one end of a main drive shaft 33. Disposed at the opposite end of the main drive shaft 33 is another set of external, crowned splines 35, adapted to be in engagement with another set of straight, internal splines defined by some form of rotary output such as a shaft or wheel hub.
- gerotor motors of the type to which the invention relates may include a rotary output shaft, supported by suitable bearings, such as is illustrated in U. S. 4,343,600, and it will be understood that the invention is not limited to any particular configuration of output shaft. It is essential only that the device include some form of shaft means operable to transmit the rotary motion of the star 23.
- the ring member 19 includes nine internal teeth 21 and the star 23 includes eight external teeth, eight orbits of the star 23 result in one complete rotation thereof and one complete rotation of the output end of the main drive shaft 33 as is well known in the art.
- the endcap member 17 includes a fluid inlet port 37 and a fluid outlet port 39.
- the endcap member 17 includes an end surface 41 in sliding sealing engagement with an end surface 42 (see FIG. 1) of the star 23 and disposed adjacent the gerotor gear set 15.
- the end surface 41 defines a fluid pressure chamber 43 which is in fluid communication with the fluid inlet port 37, through a fluid passage 36, by means of a tubular member 45 which is pressed into a circular opening defined by the endcap 17.
- the end surface 41 further defines an annular fluid pressure chamber 47 which is preferably disposed to be concentric with the fluid pressure chamber 43.
- the pressure chamber 47 is in fluid communication with the fluid outlet port 39 by means of a passage 49.
- annular fluid pressure chamber 51 Disposed radially between the fluid pressure chambers 43 and 47 is an annular fluid pressure chamber 51, which is in fluid communication with a cored passage 53, defined by the endcap member 17, by means of a generally tubular member 55.
- the tubular member 55 is pressed into a circular opening in the endcap member 17 and serves to separate the annular fluid pressure chambers 47 and 51.
- each of the valve passages 57 would typically comprise a radially oriented, milled slot, each of which would be disposed in permanent, continuous fluid communication with an adjacent one of the volume chambers 25 or 27.
- the valve passages 57 are disposed in a generally annular pattern which is concentric relative to the annular fluid pressure chambers 43, 47 and 51, as is illustrated in FIG. 2.
- the star 23 comprises an assembly of two separate parts.
- the star 23 comprises two separate powdered metal parts, including a main portion 59, which includes the external teeth, and an insert or plug 61.
- the main portion 59 and the insert 61 cooperate to define the various fluid zones, passages and ports which will be described subsequently.
- the star 23 defines a central manifold zone 63, which is in continuous fluid communication with the pressure chamber 43.
- Concentric with the manifold zone 63 is another outer manifold zone 65, which is in continuous fluid communication with the annular pressure chamber 47.
- zone in regard to the manifold zones 63, 65 and 67 will be understood by those skilled in the art to mean and include either a single opening (as in the case of the manifold zone 63), or a plurality of separate, circumferentially spaced openings (as in the case of the manifold zones 65 and 67).
- the end surface 42 of the star 23 defines a set of fluid ports 69, each of which is in fluid communication with the central manifold zone 63 by means of a fluid passage 71 (see FIG. 5A).
- a fluid passage 71 see FIG. 5A.
- the end surface 42 of the star 23 further defines a set of fluid ports 73, each of which is in fluid communication with one of the openings of the outer manifold zone 65 by means of a fluid passage 75.
- a fluid passage 75 there are eight of the fluid ports 73 and of the fluid passages 75.
- the end surface 42 of the star 23 also defines a set of fluid ports 77, each of which is in continuous fluid communication with one of the openings of the intermediate manifold zone 67 by means of a fluid passage 79.
- low-pressure exhaust fluid is communicated from the contracting volume chambers 27 through those valve passages 57 which are instantaneously in communication therewith, and this exhaust fluid then flows into certain of the fluid ports 77 which are instantaneously in communication with the particular valve passages 57 containing exhaust fluid.
- the shaft housing portion 13 defines a recess 81, and seated within the recess 81 is a pressure-balancing plate 83.
- the balancing plate 83 defines a plurality of openings 85, each of which is in communication with one of the volume chambers 25 or 27.
- Each of the openings 85 communicates with a pressure-balancing recess 87 which is disposed on the side of the plate 83 opposite the gerotor gear set 15. Items 81 through 87 have been recited herein primarily for the purpose of completeness.
- pressure balancing is generally well known in the art of gerotor motors and forms no essential part of the present invention, there will be no further detailed description of the pressure-balancing plate 83 or of the size or shape of the recesses 87. It will be understood by those skilled in the art that the pressure-balancing plate 83 may be used either to "balance” the star 23 in the axial direction, such that the hydraulic forces acting on the star 23 in opposite directions are approximately the same, or alternatively, the pressure-balancing plate 83 may be used to "overbalance" the star 23 into tight sealing engagement with the end surface 41 of the endcap member 17.
- FIG. 6 is a view partly in cross-section (on line 6-6 of FIG. 1) and partly in schematic.
- the endcap member 17 defines a spool bore 91 which is intersected by the fluid passages 36, 49, and 53, at locations axially spaced apart as shown in FIG. 6.
- the axially opposite ends of the spool bore 91 are closed by a pair of threaded fittings 93 and 95, and disposed within the spool bore 91 is a valve spool 97.
- the valve spool 97 is biased toward the left in FIG. 6 by a spring member 99, and is biased toward the right, to the position shown in FIG. 6 by fluid pressure in pressure chamber 101.
- the fluid pressure needed to bias the valve spool 97 to the position shown in FIG. 6 may be communicated to the pressure chamber 101 in any one of several ways well known to those skilled in the art, and which form no part of the present invention.
- high-pressure fluid will be present in all of the fluid ports 69 and fluid ports 77, from where high pressure will be communicated through the respective fluid passages 57 into the expanding volume chambers 25 (shading indicates high pressure fluid), causing the star 23 to orbit in a clockwise direction, while rotating in a counterclockwise direction, as viewed in FIG. 6.
- low-pressure fluid is communicated from the contracting volume chambers 27 through the respective fluid passages 57 into certain of the fluid ports 73.
- Exhaust fluid from the ports 73 is communicated through the outer manifold zone 65 to the pressure chamber 47, and from there through the fluid passage 49 to the outlet port 39. Therefore, with the valve spool 97 in the position shown in FIG. 6, high-pressure fluid is communicated to all four of the expanding volume chambers 25, while exhaust fluid is communicated from all four of the contracting volume chambers 27, and the gerotor motor operates in a normal low-speed, high-torque (LSHT) mode.
- LSHT normal low-speed, high-torque
- the device of the present invention will be described in connection with operation in the high-speed, low-torque (HSLT) mode.
- HSLT high-speed, low-torque
- the inlet port 37 there will be high pressure in only pressure chamber 43, while both of the pressure chambers 51 and 47 are in communication with low-pressure fluid, by means of the fluid passages 53 and 49, respectively.
- high-pressure fluid is communicated from the pressure chamber 43 through the central manifold zone 63 into the fluid ports 69. As may be seen in FIG. 7, this results in communication of high-pressure fluid into only two of the expanding volume chambers 25.
- exhaust fluid from the contracting volume chambers 27 is communicated through the associated fluid ports 73, outer manifold zone 65, and pressure chamber 47 as described in connection with FIG. 6.
- the fluid passages 49 and 53 are in open communication, a portion of the low-pressure exhaust fluid from the contracting volume chambers 27 is communicated through the fluid passage 53 and into the pressure chamber 51, and from there into the intermediate manifold zone 67 and through the fluid ports 77 into the other two of the expanding volume chambers 25.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Hydraulic Motors (AREA)
Abstract
Description
- This application is a continuation-in-part of corresponding application USSN 858,151, filed May 1, 1986.
- The present invention relates to rotary fluid pressure devices, and more particularly, to such devices which include gerotor displacement mechanisms utilizing low-speed, commutating valving.
- In conventional gerotor motors utilizing low-speed, commutating valving (i.e., the rotary valve element rotates at the speed of rotation of the gerotor star rather than the orbiting speed of the star) the valving action has been accomplished by means of a rotary valve member and a stationary valve member, with both valve members being separate and distinct from the gerotor displacement mechanism. One disadvantage of the conventional gerotor motor valving arrangements has been the occurrence of "timing" errors, especially in motor designs in which the rotary valve element was driven by the motor output shaft or the dogbone shaft. When torque wind-up of the dogbone shaft occurs, the relative position of the gerotor star and the rotary valve deviates from the theoretical position, resulting in an error in the valve "timing", i.e., the communication of fluid into and out of the volume chambers as they expand and contract. Another disadvantage of arrangements in which the stationary and rotary valve elements are separate from the gerotor mechanism is simply the excessive number of parts required and the resulting expense.
- It has been recognized for a number of years that one solution to the types of problems mentioned above is the provision of a gerotor motor in which a portion of the gerotor star itself comprises the rotary valve member ("valve-in-star"). It has been recognized that a valve-in-star design should substantially eliminate valve timing errors because of the fixed relationship between the star and the rotary valve ports. In addition, having fewer elements surrounded by leakage clearances and fewer elements requiring some sort of pressure balancing results in a motor capable of achieving both higher volumetric efficiency as well as higher mechanical efficiency. U. S. Patent No. 3,825,376 illustrates one fairly early attempt at a valve-in-star design. However, each of the rotary ports associated with the gerotor star opened directly into the volume chamber, thus interrupting the star profile, which has long been recognized as being undesirable.
- A more recent attempt to provide a satisfactory valve-in-star gerotor motor is illustrated in U. S. Patent No. 4,411,606, in which the "manifold valving" or directional valving occurs between the star and the endcap, while the commutating valving occurs at the axially opposite end face of the star, at the interface of the star and an adjacent valve plate. Such an arrangement effectively requires that the valving be "fixed clearance", as opposed to being pressure balanced or pressure overbalanced. In addition, the arrangement in U. S. 4,411,606 requires a plurality of axial bores extending through the star to communicate between the opposite ends of the star. If such bores are fairly small, there is too much flow restriction, and too large a pressure drop within the motor, which reduces mechanical efficiency of the motor. On the other hand, if such bores are large enough to avoid excessive flow restriction, the result is a weakening of the star.
- Accordingly, it is an object of the present invention to provide an improved low-speed, high-torque gerotor motor utilizing a valve-in-star design which substantially overcomes the problems of the prior art devices.
- It is a further object of the present invention to provide a device in which both the manifold valving action and the commutating valving action occur at the interface of the gerotor star and the endcap disposed adjacent the star.
- Low-speed, high-torque gerotor motors of the type to which this invention relates have typically been utilized in systems in which the relief valve would be set at approximately 3,500 psi, and in which the motor would operate at approximately 3,000 psi. More recently, there has been increasing demand in the marketplace for motors capable of operating at relatively high pressures, at least intermittently, in systems in which the relief valve may be set as high as 4,500 psi or even 5,000 psi.
- In the valve-in-star motor shown in above-cited 3,825,376, the variation in the number of volume chambers communicating with the ports, and the resulting torque ripple, make the motor shown therein unsuitable for high-pressure applications.
- The motor shown in above-cited 4,411,606 is similarly unsuitable for high-pressure applications because of the "fixed clearance" type of valving which is inherent by virtue of valve action occurring between opposite end faces of the star and adjacent members fixed to the end surfaces of the gerotor ring. As is well known to those skilled in the art, subjecting a fixed clearance valve to relatively higher pressures would result in excessive "cross-port" leakage, and reduced volumetric efficiency.
- Accordingly, it is another important object of the present invention to provide an improved low-speed, high-torque gerotor motor utilizing a valve-in-star design wherein the motor is capable of being used in relatively higher pressure applications.
- It has also been an object of those skilled in the art to provide a simple, but efficient, two-speed gerotor motor. As used herein, the term "two-speed" means that for any given rate of fluid flow into the motor, it is possible to select between two different motor output speeds; a high-speed (low-torque), and the conventional low-speed (high-torque). U. S. Patent No. 3,778,198 discloses the basic concept for achieving two-speed operation of a gerotor motor. The motor shown in the reference patent is of the spool valve type which has been limited to relatively lower pressures and torques, because of the fixed diametral clearance between the rotating spool valve and the adjacent cylindrical housing surface.
- More recently, U. S. Patent No. 4,480,971, assigned to the assignee of the present invention, teaches a two-speed gerotor motor of the disk valve type which, therefore, is more suited for applications requiring relatively higher pressures and torques. Although it is believed that the device shown in U. S. 4,480,971 will result in a commercially successful two-speed gerotor motor, the design disclosed therein is somewhat large and complex, and is subject to the pressure and torque limitations inherent in disk valve gerotor motors.
- Accordingly, it is still another object of the present invention to provide an improved low-speed, high-torque gerotor motor utilizing a valve-in-star design which includes the ability for the motor to operate in either the low-speed, high-torque mode or the high-speed, low-torque mode.
- The above and other objects of the present invention are accomplished by the provision of an improved rotary fluid pressure device of the general type set forth in U. S. Patent No. 4,411,606 wherein the device comprises a housing means including an endcap member defining a fluid inlet port and a fluid outlet port; a gerotor gear set associated with said housing means and including an internally-toothed ring member and an externally-toothed star member eccentrically disposed within the ring member; either the ring member or the star member has orbital movement relative to the other of the members, and the star member has rotational movement relative to the ring member and the housing means; the internal teeth of the ring member and the external teeth of the star interengage to define a plurality N + 1 of expanding and contracting fluid volume chambers during the relative orbital and rotational movements; the device includes a shaft means and means operable to transmit the rotational movement of the star member to the shaft means; the endcap member defines a first fluid pressure chamber in continuous communication with either the inlet or outlet port, and a second fluid pressure chamber in continuous communication with the other port; the star member defines a first manifold zone in continuous fluid communication with the first fluid pressure chamber, and a second manifold zone in continuous fluid communication with the second fluid pressure chamber; the star member includes an end surface disposed toward the endcap member and defining first and second sets of fluid ports, the first set of fluid ports being in continuous fluid communication with the first manifold zone, and the second set of fluid ports being in continuous fluid communication with the second manifold zone.
- The improved device is characterized by: (a) the end surface of the star member is in sliding, sealing engagement with an adjacent surface of the endcap member; (b) the endcap member defines a third fluid pressure chamber and a control fluid passage in communication with the third fluid pressure chamber; (c) the star member defines a third manifold zone in continuous fluid communication with the third fluid pressure chamber; (d) the end surface of the star member defines a third set of fluid ports in continuous fluid communication with the third manifold zone; (e) the adjacent surface of the endcap member defines a plurality N + 1 of valve passages, each of the valve passages being in continuous fluid communication with one of the expanding and contracting fluid volume chambers; (f) the first, second and third sets of fluid ports are in commutating fluid communication with the plurality N + 1 of valve passages, defined by the endcap member, in response to the relative rotational movement of the star member; and (g) a valve means is selectively operable between a first condition communicating the control fluid passage to the first fluid pressure chamber, and a second condition communicating the control fluid passage to the second fluid pressure chamber.
-
- FIG. 1 is an axial cross-section of a normally low-speed, high-torque gerotor motor made in accordance with the present invention.
- FIG. 2 is a transverse cross-section, showing the surface of the endcap member, taken on line 2-2 of FIG. 1, and on the same scale.
- FIG. 3 is a transverse cross-section, showing the end surface of the gerotor gear set adjacent the endcap, taken on line 3-3 of FIG. 1, and on the same scale.
- FIG. 4 is an enlarged plan view, similar to FIG. 3, showing a preferred embodiment of a gerotor star made in accordance with the present invention.
- FIGS. 5a, 5b, and 5c are fragmentary, somewhat simplified cross-sections taken through the gerotor star of FIG. 4 at three different locations, and on the same scale as FIG. 4.
- FIGS. 6 and 7 are views partly in schematic, and partly in transverse cross-section on line 6-6 of FIG. 1, illustrating the operation of the hydraulic circuit associated with the present invention.
- Referring now to the drawings, which are not intended to limit the invention, FIG. 1 illustrates a low-speed, high-torque gerotor motor. The hydraulic motor shown in FIG. 1 comprises a plurality of sections secured together, such as by a plurality of bolts 11. The sections of the motor include a
shaft housing portion 13, agerotor displacement mechanism 15, and anendcap member 17. - The gerotor displacement mechanism 15 (best seen in FIG. 3) is well known in the art, is shown and described in great detail in U. S. Patent No. 4,343,600, which is assigned to the assignee of the present invention, is incorporated herein by reference, and therefore will be described only briefly herein. More specifically, the
displacement mechanism 15 is a Geroler® gear set comprising an internally-toothed ring member 19 defining a plurality of generally semi-cylindrical openings, with acylindrical roller member 21 disposed in each of the openings, and serving as the internal teeth of thering member 19. Eccentrically disposed within thering 19 is an externally-toothed star 23, typically having one less external tooth than the number ofinternal teeth 21, thus permitting thestar 23 to orbit and rotate relative to thering member 19. The relative orbital and rotational movement between thering 19 and thestar 23 defines a plurality of expandingfluid volume chambers 25 and a plurality of contractingfluid volume chambers 27, as is well known in the art. - Referring again primarily to FIG. 1, the
star 23 defines a plurality of straight,internal splines 29, which are in engagement with a set of external crownedsplines 31 formed on one end of amain drive shaft 33. Disposed at the opposite end of themain drive shaft 33 is another set of external, crownedsplines 35, adapted to be in engagement with another set of straight, internal splines defined by some form of rotary output such as a shaft or wheel hub. As is well known to those skilled in the art, gerotor motors of the type to which the invention relates may include a rotary output shaft, supported by suitable bearings, such as is illustrated in U. S. 4,343,600, and it will be understood that the invention is not limited to any particular configuration of output shaft. It is essential only that the device include some form of shaft means operable to transmit the rotary motion of thestar 23. - In the subject embodiment, because the
ring member 19 includes nineinternal teeth 21 and thestar 23 includes eight external teeth, eight orbits of thestar 23 result in one complete rotation thereof and one complete rotation of the output end of themain drive shaft 33 as is well known in the art. - Referring now to FIG. 2, in conjunction with FIG. 1, the
endcap member 17 includes afluid inlet port 37 and afluid outlet port 39. Theendcap member 17 includes anend surface 41 in sliding sealing engagement with an end surface 42 (see FIG. 1) of thestar 23 and disposed adjacent thegerotor gear set 15. Theend surface 41 defines afluid pressure chamber 43 which is in fluid communication with thefluid inlet port 37, through afluid passage 36, by means of a tubular member 45 which is pressed into a circular opening defined by theendcap 17. Theend surface 41 further defines an annularfluid pressure chamber 47 which is preferably disposed to be concentric with thefluid pressure chamber 43. Thepressure chamber 47 is in fluid communication with thefluid outlet port 39 by means of apassage 49. - Disposed radially between the
fluid pressure chambers fluid pressure chamber 51, which is in fluid communication with acored passage 53, defined by theendcap member 17, by means of a generally tubular member 55. The tubular member 55 is pressed into a circular opening in theendcap member 17 and serves to separate the annularfluid pressure chambers - The
end surface 41 of theendcap member 17 further defines a plurality ofstationary valve passages 57, also referred to in the art as "timing slots". In the subject embodiment, each of thevalve passages 57 would typically comprise a radially oriented, milled slot, each of which would be disposed in permanent, continuous fluid communication with an adjacent one of thevolume chambers valve passages 57 are disposed in a generally annular pattern which is concentric relative to the annularfluid pressure chambers - Referring now primarily to FIG. 4, in conjunction with FIG. 1, the externally-
toothed star 23 will be described in greater detail. Although not an essential feature of the invention, it is preferable that thestar 23 comprise an assembly of two separate parts. In the subject embodiment, thestar 23 comprises two separate powdered metal parts, including amain portion 59, which includes the external teeth, and an insert or plug 61. Themain portion 59 and theinsert 61 cooperate to define the various fluid zones, passages and ports which will be described subsequently. - Referring now primarily to FIGS. 4 and 5, the
star 23 defines acentral manifold zone 63, which is in continuous fluid communication with thepressure chamber 43. Concentric with themanifold zone 63 is anotherouter manifold zone 65, which is in continuous fluid communication with theannular pressure chamber 47. Disposed radially between themanifold zones intermediate manifold zone 67, which is in continuous fluid communication with theannular pressure chamber 51. As may best be seen in FIG. 4, the use of the term "zone" in regard to themanifold zones manifold zones 65 and 67). - The
end surface 42 of thestar 23 defines a set offluid ports 69, each of which is in fluid communication with thecentral manifold zone 63 by means of a fluid passage 71 (see FIG. 5A). In the subject embodiment, there are four of theports 69 andfluid passages 71. - The
end surface 42 of thestar 23 further defines a set offluid ports 73, each of which is in fluid communication with one of the openings of theouter manifold zone 65 by means of afluid passage 75. In the subject embodiment, there are eight of thefluid ports 73 and of thefluid passages 75. - The
end surface 42 of thestar 23 also defines a set offluid ports 77, each of which is in continuous fluid communication with one of the openings of theintermediate manifold zone 67 by means of afluid passage 79. In the subject embodiment, there are four of thefluid ports 77 and of thefluid passages 79. - As is well known to those skilled in the art, because there are nine of the
internal teeth 21, there are nine of thevalve passages 57. As thestar 23 orbits and rotates relative to thering member 19, the set of eightfluid ports valve passages 57. The result is that communication occurs only between thefluid ports valve passages 57 which are instantaneously in fluid communication with one of the expandingvolume chambers 25. At the same time, low-pressure exhaust fluid is communicated from thecontracting volume chambers 27 through thosevalve passages 57 which are instantaneously in communication therewith, and this exhaust fluid then flows into certain of thefluid ports 77 which are instantaneously in communication with theparticular valve passages 57 containing exhaust fluid. - Referring now primarily to FIG. 1 again, it may be seen that the
shaft housing portion 13 defines arecess 81, and seated within therecess 81 is a pressure-balancingplate 83. The balancingplate 83 defines a plurality ofopenings 85, each of which is in communication with one of thevolume chambers openings 85 communicates with a pressure-balancing recess 87 which is disposed on the side of theplate 83 opposite the gerotor gear set 15.Items 81 through 87 have been recited herein primarily for the purpose of completeness. Because pressure balancing is generally well known in the art of gerotor motors and forms no essential part of the present invention, there will be no further detailed description of the pressure-balancingplate 83 or of the size or shape of the recesses 87. It will be understood by those skilled in the art that the pressure-balancingplate 83 may be used either to "balance" thestar 23 in the axial direction, such that the hydraulic forces acting on thestar 23 in opposite directions are approximately the same, or alternatively, the pressure-balancingplate 83 may be used to "overbalance" thestar 23 into tight sealing engagement with theend surface 41 of the endcapmember 17. - Reference will now be made primarily to FIG. 6 which is a view partly in cross-section (on line 6-6 of FIG. 1) and partly in schematic. The endcap
member 17 defines a spool bore 91 which is intersected by thefluid passages fittings valve spool 97. Thevalve spool 97 is biased toward the left in FIG. 6 by aspring member 99, and is biased toward the right, to the position shown in FIG. 6 by fluid pressure inpressure chamber 101. The fluid pressure needed to bias thevalve spool 97 to the position shown in FIG. 6 may be communicated to thepressure chamber 101 in any one of several ways well known to those skilled in the art, and which form no part of the present invention. - With the
valve spool 97 biased to the position shown in FIG. 6, and assuming that theinlet port 37 is communicated to a source of high-pressure fluid, there will be high pressure in both of thefluid passage pressure chambers star 23 orbits and rotates, high pressure will be communicated from thepressure chamber 43 into thecentral manifold zone 63, and from thepressure chamber 51 into theintermediate manifold zone 67. Therefore, high-pressure fluid will be present in all of thefluid ports 69 andfluid ports 77, from where high pressure will be communicated through the respectivefluid passages 57 into the expanding volume chambers 25 (shading indicates high pressure fluid), causing thestar 23 to orbit in a clockwise direction, while rotating in a counterclockwise direction, as viewed in FIG. 6. At the same time, low-pressure fluid is communicated from thecontracting volume chambers 27 through the respectivefluid passages 57 into certain of thefluid ports 73. Exhaust fluid from theports 73 is communicated through theouter manifold zone 65 to thepressure chamber 47, and from there through thefluid passage 49 to theoutlet port 39. Therefore, with thevalve spool 97 in the position shown in FIG. 6, high-pressure fluid is communicated to all four of the expandingvolume chambers 25, while exhaust fluid is communicated from all four of thecontracting volume chambers 27, and the gerotor motor operates in a normal low-speed, high-torque (LSHT) mode. - Referring now to FIG. 7, the device of the present invention will be described in connection with operation in the high-speed, low-torque (HSLT) mode. In order to select the HSLT mode, it is necessary to reduce the fluid pressure in the
pressure chamber 101 sufficiently to permit thespring member 99 to bias thevalve spool 97 to the position shown in FIG. 7 in which thefluid passages fluid passage 36. In this mode of operation, with high-pressure communicated to theinlet port 37, there will be high pressure inonly pressure chamber 43, while both of thepressure chambers fluid passages - In the HSLT mode, high-pressure fluid is communicated from the
pressure chamber 43 through thecentral manifold zone 63 into thefluid ports 69. As may be seen in FIG. 7, this results in communication of high-pressure fluid into only two of the expandingvolume chambers 25. At the same time, exhaust fluid from thecontracting volume chambers 27 is communicated through the associatedfluid ports 73,outer manifold zone 65, andpressure chamber 47 as described in connection with FIG. 6. However, because thefluid passages contracting volume chambers 27 is communicated through thefluid passage 53 and into thepressure chamber 51, and from there into theintermediate manifold zone 67 and through thefluid ports 77 into the other two of the expandingvolume chambers 25. In other words, with the same volume of high-pressure fluid communicated to theinlet port 37 as in the LSHT mode will now, in the HSLT mode, be communicated to only half of the expandingvolume chambers 25, thus resulting in orbital and rotational movement of thestar 23 at twice the speed, but with only half as much torque. - Although the present invention has been described in connection with an embodiment wherein the
star 23 rotates at twice the speed, but only half the torque in the HSLT mode, it should be clear to those skilled in the art that the invention is not so limited. The number of ports and passages, etc., can be varied from that shown herein to achieve speed ratios other than 2:1. The invention has been described in great detail sufficient to enable one skilled in the art to make and use the same. It is apparent that various alterations and modifications will occur to those skilled in the art, and it is intended to include all such alterations and modifications as part of the invention, insofar as they come within the scope of the appended claims.
Claims (15)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US07/007,882 US4715798A (en) | 1986-05-01 | 1987-01-28 | Two-speed valve-in star motor |
US7882 | 2001-12-06 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0276680A2 true EP0276680A2 (en) | 1988-08-03 |
EP0276680A3 EP0276680A3 (en) | 1989-05-10 |
EP0276680B1 EP0276680B1 (en) | 1991-01-09 |
Family
ID=21728611
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP88100323A Expired - Lifetime EP0276680B1 (en) | 1987-01-28 | 1988-01-12 | Two-speed valve in-star motor |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0276680B1 (en) |
JP (1) | JPH0751938B2 (en) |
DE (1) | DE3861468D1 (en) |
DK (1) | DK40388A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2012075625A1 (en) * | 2010-12-07 | 2012-06-14 | White (China) Drive Products Co., Ltd | Distributor assembly for two-speed gerotor device |
WO2012018878A3 (en) * | 2010-08-03 | 2013-09-19 | Eaton Corporation | Balance plate assembly for a fluid device |
US11493018B2 (en) | 2020-01-03 | 2022-11-08 | Parker-Hannifin Corporation | Hydraulic motor with anti-cogging features |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2764961B2 (en) * | 1988-11-18 | 1998-06-11 | ヤマハ株式会社 | Electronic musical instrument |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2196678A6 (en) * | 1972-08-18 | 1974-03-15 | Danfoss As | |
US3892503A (en) * | 1974-01-23 | 1975-07-01 | Sperry Rand Corp | Apparatus and method for multiple mode motor |
DE3008832A1 (en) * | 1979-03-09 | 1980-09-18 | Tokyo Keiki Kk | Reversible-flow rotary-piston engine - has disc between valve plate and working fluid manifolds for controlling flow to chambers in groups |
US4480971A (en) * | 1983-01-17 | 1984-11-06 | Eaton Corporation | Two-speed gerotor motor |
-
1988
- 1988-01-12 DE DE8888100323T patent/DE3861468D1/en not_active Expired - Lifetime
- 1988-01-12 EP EP88100323A patent/EP0276680B1/en not_active Expired - Lifetime
- 1988-01-26 JP JP63015706A patent/JPH0751938B2/en not_active Expired - Lifetime
- 1988-01-27 DK DK040388A patent/DK40388A/en not_active Application Discontinuation
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2196678A6 (en) * | 1972-08-18 | 1974-03-15 | Danfoss As | |
US3892503A (en) * | 1974-01-23 | 1975-07-01 | Sperry Rand Corp | Apparatus and method for multiple mode motor |
DE3008832A1 (en) * | 1979-03-09 | 1980-09-18 | Tokyo Keiki Kk | Reversible-flow rotary-piston engine - has disc between valve plate and working fluid manifolds for controlling flow to chambers in groups |
US4480971A (en) * | 1983-01-17 | 1984-11-06 | Eaton Corporation | Two-speed gerotor motor |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2012018878A3 (en) * | 2010-08-03 | 2013-09-19 | Eaton Corporation | Balance plate assembly for a fluid device |
US8821139B2 (en) | 2010-08-03 | 2014-09-02 | Eaton Corporation | Balance plate assembly for a fluid device |
WO2012075625A1 (en) * | 2010-12-07 | 2012-06-14 | White (China) Drive Products Co., Ltd | Distributor assembly for two-speed gerotor device |
US8684710B2 (en) | 2010-12-07 | 2014-04-01 | White (China) Drive Products Co., Ltd. | Distributor assembly for two-speed gerotor device |
US11493018B2 (en) | 2020-01-03 | 2022-11-08 | Parker-Hannifin Corporation | Hydraulic motor with anti-cogging features |
Also Published As
Publication number | Publication date |
---|---|
EP0276680B1 (en) | 1991-01-09 |
DK40388A (en) | 1988-07-29 |
DK40388D0 (en) | 1988-01-27 |
JPH0751938B2 (en) | 1995-06-05 |
EP0276680A3 (en) | 1989-05-10 |
JPS63195386A (en) | 1988-08-12 |
DE3861468D1 (en) | 1991-02-14 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US4715798A (en) | Two-speed valve-in star motor | |
EP0116217B1 (en) | Two-speed gerotor motor | |
US4493622A (en) | Variable displacement motor | |
EP0213154B1 (en) | Rotary motion fluid apparatus | |
EP0408011B1 (en) | Gerotor motor and improved pressure balancing therefor | |
EP0054161B1 (en) | Gerotor gear set device with integral rotor and commutator | |
US6126424A (en) | Transistion valving for gerotor motors | |
EP0394821B1 (en) | Valve for gerotor motor | |
US3910732A (en) | Gerotor pump or motor | |
EP0756085B1 (en) | Gerotor motor and commuting valve | |
EP0302728A2 (en) | Rotary valve plate | |
US5228846A (en) | Spline reduction extension for auxilliary drive component | |
EP1045147A2 (en) | Two speed gerotor motor | |
EP0276680B1 (en) | Two-speed valve in-star motor | |
US4756676A (en) | Gerotor motor with valving in gerotor star | |
EP0412403B1 (en) | Rotary fluid pressure device and improved stationary valve plate therefor | |
US5593296A (en) | Hydraulic motor and pressure relieving means for valve plate thereof | |
US3352247A (en) | Fluid pressure device with dual feed and exhaust | |
EP0387713A3 (en) | Gerotor type hydraulic motor or pump | |
US4334843A (en) | Gerotor machine with valve plates attached to wheel gear | |
US4592704A (en) | Motor with improved low-speed operation | |
US6679691B1 (en) | Anti cavitation system for two-speed motors | |
JP3051238B2 (en) | Hydraulic motor | |
EP1158165A2 (en) | Gyrotor hydraulic motor | |
GB2202006A (en) | Rotary fluid pressure device |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Kind code of ref document: A2 Designated state(s): DE FR GB IT |
|
PUAL | Search report despatched |
Free format text: ORIGINAL CODE: 0009013 |
|
AK | Designated contracting states |
Kind code of ref document: A3 Designated state(s): DE FR GB IT |
|
17P | Request for examination filed |
Effective date: 19890908 |
|
17Q | First examination report despatched |
Effective date: 19900509 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): DE FR GB IT |
|
ITF | It: translation for a ep patent filed |
Owner name: ING. C. GREGORJ S.P.A. |
|
REF | Corresponds to: |
Ref document number: 3861468 Country of ref document: DE Date of ref document: 19910214 |
|
ET | Fr: translation filed | ||
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 19981211 Year of fee payment: 12 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 19990107 Year of fee payment: 12 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 19990128 Year of fee payment: 12 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20000112 |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20000112 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20000929 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20001101 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: IT Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED. Effective date: 20050112 |