US3656405A

US3656405A - Pressurized medium motor

Info

Publication number: US3656405A
Application number: US88446A
Authority: US
Inventors: Karl Klinkhammer
Original assignee: Gebr Dickertmann Hebezeugfabrik AG
Current assignee: Gebr Dickertmann Hebezeugfabrik AG
Priority date: 1969-11-11
Filing date: 1970-11-10
Publication date: 1972-04-18
Anticipated expiration: 1989-04-18
Also published as: DE2054358A1; GB1328656A; NL7016518A; AT306472B; CH520263A; FR2069166A5; BE758736A

Abstract

A pressurized medium motor comprising a housing, a plurality of opposed pivotally mounted piston and cylinder units in the housing and adapted to be successively supplied with pressurized medium, each unit acting on eccentric drive means geared positively or non-positively with the housing, the opposed piston and cylinder units with the eccentric drives forming a polygon having a substantially constant circumference with varying side lengths, with an adjacent pair of units each having one piston end acting on a common eccentric part of an eccentric drive, each such unit being provided with at least one passage acting as a supply or discharge means for the pressurized medium, the said passage(s) being alternately connected automatically to pressure and exhaust passage, the said pressure and exhaust passages being connected in turn to all the units.

Description

nited States Patent linkhammer [151 3,656,405 [451 Apr. 18, 1972 [54] PRESSURIZED MEDIUM MOTOR [21] Appl. No.: 88,446

FOREIGN PATENTS OR APPLICATIONS 1,924,837 l/l970 Germany ..92/75 Primary Examiner-Paul E. Maslousky Attorney-Edmund M. Jaskiewicz [57] ABSTRACT A pressurized medium motor comprising a housing, a plurality of opposed pivotally mounted piston and cylinder units in the housing and adapted to be successively-supplied with pres surized medium, each unit acting on eccentric drive means geared positively or non-positively with the housing, the opposed piston and cylinder units with the eccentric drives'forming a polygon having a substantially constant circumference with varying side lengths, with an adjacent pair of units each having one piston end acting on a common eccentric part of an eccentric drive, each such unit being provided with at least one passage acting as a supply or discharge means for the pressurized medium, the said passage(s) being alternately connected automatically to pressure and exhaust passage, the said pressure and exhaust passages being connected in turn to all the units.

8 Claims, 4 Drawing Figures 100 27a 2s 3o 16 27h PATENTEUAPR 18 ma SHEET 2 0F 2 l fw fr@ I L LLL lNvliN'l'olz:

Karl Klinkhummer PRESSURIZED MEDIUM MOTOR Prior Application In Austria on Nov. l1, l969 and numbered A 10578/69 The invention concerns a motor adapted to be driven by means of a pressurized medium such as a liquid or air.

lt is an object of the invention to provide a pressurized medium motor which is relatively small but yet provides a high torque without the use of reduction gears and which can operate continuously.

ln accordance with the invention there is provided a pressurized medium motor in a housing, having a plurality of opposed piston and cylinder units adapted to be supplied with pressurized medium, the units being pivotally mounted and connected with the eccentric drive means running on the inside surface ofthe housing, each opposed piston and cylinder unit being provided with at least one pressurized medium passage to act as inlet and outlet, the said passage being connected alternately and automatically to pressurized medium passages for the inlet and outlet of the pressurized medium associated with each opposed piston and cylinder unit.

Preferably each opposed piston and cylinder unit is provided with two pressurized medium passages which are alternately connected with a pressurized medium supply and medium discharge common to all such units. The opposed piston and cylinder units with their eccentric drives form a polygon of varying shape, the lengths of the sides varying in dependence upon the positions of the various pistons while the circumference of the articulated polygon remains substantially constant.

Adjacent opposed piston and cylinder units each have a piston end supported on an eccentric part of a common drive, the pistons exerting pressure on the eccentric to produce the drive.

The drive means form with the housing a reduction gear; to this end the eccentrics may be provided with gear pinions which mesh with a toothed inside surface ofthe housing; alternatively the eccentrics are provided with friction gears which engage with a smooth inside surface of the housing to produce a friction drive.

The opposed piston and cylinder units and the eccentric drives are mounted pivotally or rotatably in common bearing plates. Each opposed piston and cylinder unit has a cylinder block in the bore of which two opposed pistons are displaceably mounted, and held against the adjacent eccentrics by means ofa spring.

Two passages extending from the cylinder bore of each cylinder block towards the housing center, act as supply and discharge passages and are connected alternately to two supply and discharge passages located within a bearing plate on different levels, and to an annular chamber connected to the supply or discharge passages which supplies the pressurized medium and provides a discharge path.

The pistons ofthe units are supplied in succession with the pressurized medium and each unit operates on particular eccentrics so that a substantially uniform drive results on the housing or bearing plate.

During rotation of an eccentric drive means, the associated opposed piston and cylinder units execute a pendulum motion about the region of the supply and discharge passages associated with each unit on the bearing plate, so that the passage from the cylinder block is alternately connected to the supply and discharge passages on the bearing plate side and hence to the central passages.

The motor of the invention is of simple structure, reliable in operation and economical to produce.

An advantage of the invention resides in that the motor is provided with a built-in reduction gear thus rendering additional gears superfluous. This motor is a slow speed runner which has a high torque which is constant over its whole speed range. This torque is readily varied by varying of the operating medium.

Owing to the arrangement of the opposed piston and cylinder units which engage the housing to be rotated at a fairly large radius relative to the axis of rotation,

balanced torque is obtained; the gear ratio obtained between the piston and cylinder units and the drum renders extra gearing superfluous.

A motor in accordance with the invention provides a shockproof start under load from any position, and permits an accurately predetermined acceleration and deceleration characteristic.

The motor also affords accurate load, speed, and revolution control and can be used as a positioning device.

The motor is applicable more particularly to lifting tackle, the lifting height and load being under exact control.

The motor may be incorporated as a direct drive in pulleys such as cable drums, wheel bosses or the like.

Reference should now be made to the accompanying drawings in which:

FIG. l is a cross section through a motor having a plurality of opposed piston and cylinder units pivotally mounted in a housing;

FIG. 2 is a section through an opposed piston and cylinder unit taken on the line I-I in FIG. 1,

FIG. 3 is a section through the same motor taken on the line II-II of FIG. l,

FIG. 4 is a developed view of the connecting passages in the region of the ringed portion A in FIG. 3.

A pressurized medium motor, more particularly a hydraulic motor has a housing 10 in which a plurality of opposed piston and cylinder units 11, l2, 13, 14 and mounted pivotally and successively supplied with a pressurized medium such as oil or air.

The opposed piston and cylinder units 1l to 14 are connected with

eccentric drives

15, 16, 17, 18 which are positively or frictionally coupled to the housing, so that the eccentric drives l5 to 18 produce a rotational connection between the units 11 to 14 and the housing l0.

The housing 10 is circular, but may also be made as an oval. In the housing 10 there are four opposed piston and cylinder units 11 to 14 together with four eccentric drives 15 to 18, so that each two adjacent units 1l to 14 cooperate with one eccentric drive 15 to 18.

lt is possible to provide the housing 10 with three or with `more than four, for example, six or eight units and corresponding eccentric drives.

Each opposed unit l1 to 14 is provided with at least one pressurized medium passage as supply or discharge, which is alternately and automatically connectable with fluid medium passages to effect forward motion or reverse motion of the units l1 to 14.

As shown, each opposing unit 14 is provided with two pressurized

medium passages

19, 20 as supply or discharge passages, which are alternately connected automatically with a central medium forward motion passage 21 and a central medium reverse motion passage 22, the passages being common to all units.

The opposed piston and cylinder units 11 to 14 with their eccentric drives l5 to 18 form a movable polygon having sides of varying length while the circumference of the polygon remains substantially constant.

All units 1l to 14 are of identical formation. Thus, each unit 1l to 14 is provided with a cylinder block 23 which is pivotally mounted on

lateral bearing plates

25a and 25b having two central bearings 24 aligned at right angles to the direction of piston movement. Each unit 11 to 14 has a cylinder bore 26 in its cylinder block 23 in which two opposed pistons 27 are displaceably mounted.

The end 27a of each piston 27 has an abutment surface 27b which is of less cross-sectional area than the associated piston, and the end may be stepped.

The eccentric drives 15 to 18 with the housing 10 form a reduction gear. For effecting a positive connection between the eccentric drives 15 to 18 and housing 10, the housing l0 is provided on the inside surface with an internal toothed ring 10a with which the eccentric drives 15 to 18 mesh by means of a high pinions 32 provided on both sides of the eccentric 30.

A non-positive connection between the eccentric drives 15 to 18 and housing l0 to form a reduction gear may be frictional, thus the inside surface of the housing is provided with a smooth surface and the pinions of the crank drives 15 to 18 are replaced by friction wheels or rollers.

As shown, the piston and cylinder units l1 to 14 and their mounting plates are stationary and the housing is rotatable. Alternatively the housing 10 may be stationary and the units 11 to 14 with their mounting plates may be rotatable within the housing 10.

Each unit 11 to 14 is provided in its cylinder block 23 with two pressurized

medium passages

19, 20 acting as supply or discharge passages, these passages being preferably at right angles to the direction of piston movement and arranged radially and parallel, side by side, in the bearing extensions, in the region of a bearing plate 25a or 2517. These two pressurized

medium passages

19, 20 are connected to the chamber 26 via a common axial connecting passage 33. Within the

bearing plate

25a or 25b, and near the two pressurized

medium passages

19, 20 each cylinder block 23 has two pressurized

medium passages

34, 35 associated therewith as supply or return passages at different levels relative to one another, which passages are connected to the forward and

reverse fluid passages

21, 22. The two

annular chambers

36, 37 are separated by a distance corresponding to the distance between the

passages

19, 20, and are formed by axial annular grooves which on the casing side are located in a shaft 38 and connected by the upstream and downstream flow of the medium. The

passages

34, 35 alternately connect the pressurized

medium passages

19, 20 of the cylinder blocks 23 to corresponding

annular grooves

36, 37; the

passages

34, 35 are spaced to correspond with the spacing of the

passages

19, 20 and

annular grooves

36, 37.

The pivotal point of each unit 1l to 14 is at a greater radius than the length of the orifices of the supply and

discharge passages

34, 35 together with the cylinder block-

side passages

19, 20. The inlet and

outlet passages

21, 22 lead into the

annular grooves

36, 37 via passages 21a, 22a extending outwards at an angle.

Two

opposite units

11 and 13, or 12 and 14, are actuated in opposition to each other, so that if one unit is coupled to the pressure supply the other unit is coupled to the exhaust. In the position of the units 1l to 14 as shown in FIG. 1 of' the drawings unit 11 is located in the charge position, i.e. the pistons 27 of unit 11 are being supplied with pressurized medium; they are pushing oppositely outwards and thus act on the two eccentric drives and 16. Unit 12 is at the beginning of a power stroke i.e. the pistons 27 of this unit are located in the retracted position one against the other, and are about to be supplied with pressurized medium; unit 13 is connected to exhaust and unit 14 is about to be so connected.

The mode of operation ofthe motor is as follows:

As shown, unit ll is located in a driving position, with its pressurized fluid passage 19 connected to the annular supply groove 36 via the inclined supply passage 34, in which groove the supply passage 21 of the medium ends. The pressurized medium flows from the passage 2l via the annular groove 36, the inclined passage 34, the supply passage 19 and the connecting passage 33 into the cylinder space 26, acts on the two opposed pistons 27 and presses them outwards. These two pistons now act on the eccentric 30 of the two

drives

15 and 16 which are positively connected to the housing, and impart rotation thereto (see direction of arrow on the eccentric, in FIG. 1). The

eccentric drives

15, 16 also engage the housing l0 and rotate it in the same direction (see external arrow, FIG. 1).

The action of the unit 11 rotates all the eccentric drives 15 to 18 and during this rotation all units 11 to 14 pivot about their bearing extensions 24. The opposed pistons 27 of unit 11 continue to press on the two eccentric parts 30 of the

drives

15, 16 until the unit assumes dead center position, i.e. until the eccentrics are fully extended in line with the longitudinal axes ofthe pistons. In this position filling the unit 11 and its action to rotate the eccentric drives are ended. The rotation of the drives causes all units 11 to 14 to be pivotally moved, so that unit 12 now assumes a filling position and unit 14 an emptying position, while the two opposite units 11 and 13 are at a zero position. During filling of unit 11, unit 13 was in the emptying position and the two

units

12, 14 passed through a zero posi tion their

passages

19, 20 are blocked between the two inclined supply and discharge

passages

34, 35. Filling of unit 12 commences before unit 11 is completely filled, so that the piston driving actions merge into and overlap one another, one unit taking up the drive before the end of the drive of the previous unit to provide continuous rotation of the housing. Unit 12 now progressively rotates the two eccentric parts 30 of the

drives

16 and 17, all units 11 to 14 being pivoted, and unit 14 is emptied. The two other units 11, 13 have their supply and discharge

passages

19, 20 swung between the two

inclined passages

34, 35 towards the upstream (or downstream) passage; thus unit 1l moves so as to become connected to the return exhaust passage 35, and unit 13 so as to become connected to the supply passage 34. When the filling of unit 12 is completed, unit 13 has its supply passage 19 connected to the supply passage 34 and is filled in turn. At the same time unit 11 has its discharge passage 20 coupled to exhaust passage 35 and can thus be emptied. After unit 13 is filled, the oscillation of the units moves unit 14 into the filling position while unit 12 is emptied.

The two supply and discharge

passages

19, 20 of all units 1l to 14 thus move, due to the pivotal mounting of the cylinder blocks, between the inclined supply and

exhaust passages

34, 35 associated with each unit 11 to 14 and hence the cylinders arrive successively in a filling position.

The annular groove 36 connected to the supply of the medium, and the supply passage 34 leading thereto, are constantly under pressure. The movement of the supply and discharge

passages

19, 20 on the cylinder block side is shown in FlG. 4 by the arrow. A slight overlap of the supply passage 19 with the inclined supply passage initiates filling, and complete register of both

passages

19, 34 provides maximum supply to the pistons 27 with pressurized medium. Near the end stage of filling, the supply passage 19 swings over the supply passage 34 and thus becomes only partly in register therewith.

The displacement of the opposed pistons 27 of each unit 11 to 14 causes rotation of the eccentric drives l5 to 18 and hence rotation of the housing 10. Each drive 15 to 18 is rotated through a predetermined angular region of rotation and then a subsequent unit takes over further rotation, so that the various drives are translated into a uniform rotary movement ofthe housing.

Compression springs 31 retain each unit 11 to 14 in connection with the drives l5 to 18, so that during rotation of the drives a corresponding pivotal movement of the units 11 to 14 occurs so that their two supply and discharge

passages

19, 20 are caused sequentially to assume a filling position (connection of passage 19 with passage 34), a zero position (passage 19 assumes a position between the two passages 34, 35), or an emptying position (discharge passage 20 connected to discharge passage 35).

It is within the scope of the invention to provide each unit 11 to 14 only with one passage to act as both inlet and outlet, and this passage may be bifurcated in the region of the supply and discharge

passages

34, 35.

Iclaim:

1. A pressurized medium motor comprising a housing, at least one base plate, a plurality of opposed piston and cylinder units within said housing and mounted on said base plate; bearing extensions on said units whereby each said unit can rock about a center; eccentric drives acted upon by said pistons, driving means interconnecting said drives and said housing, said piston and cylinder units together with said eccentric drives forming a polygon having a constant circumference but with sides of variable length depending on the positions of said pistons; one piston of each pair of adjacent piston and cylinder units acting on a single one of said eccentric drives; at least one pressurized medium passage to each unit; and fluid supply and exhaust passages alternately connectable to each piston and cylinder unit as a result of rotation of said motor.

2. A pressurized medium motor as recited in claim l, further comprising two fluid passages for each said opposed piston and cylinder unit, a common pressurized medium supply and a common exhaust for all said units, and means for connecting said units in a predetermined sequence to said supply and exhaust via said two passages.

3. A pressurized medium motor as recited in claim 1 wherein all opposed piston and cylinder units are of identical construction, characterised by location of said units in diametrically opposite pairs, with means for actuating the units of a pair in opposite sense.

4. A pressurized medium motor as recited in claim l comprising a toothed ring located inside said housing, and at least one pinion wheel on each said eccentric drives meshing with said toothed ring to form a reduction gear.

5. A pressurized medium motor as recited in claim l comprising two parallel base plates, bearing pins on said eccentric drives and bearing extensions on said units, and bearing surfaces defined by said plates to receive said bearing pins and bearing extensions so that said eccentric drives can rotate and said units can rock.

6. A pressurized medium motor as recited in claim 5 characterized by the feature that each eccentric drive comprises an eccentric of cylindrical form, said eccentric being secured to said bearing pins and to at least one pinion wheel.

7. A pressurized medium motor as recited in claim l, wherein each opposed piston and cylinder unit consists of a cylinder block dening a bore therein; two oppositely moving pistons located in said bore; a compression spring between said pistons, a rod extension of each said piston of reduced section and extending outwards of said cylinder, and an eccentric-engaging surface on the outward end of each said rod extension.

8. A pressurized medium motor as recited in claim 7, wherein a bearing extension of each cylinder block defines two passages one to supply pressure medium and one for exhaust, said passages being arranged at an angle to the direction of piston movement and parallel to one another, said two passages joining one end of a common connecting passage extending along the axis of said bearing extension, the other end of said common passage terminating in the respective cylinder bore, and wherein one bearing plate denes two annular passages as supply or exhaust for said medium, said annular passages being common to all said opposed piston and cylinder units and being in fluid transmitting connection with said passages in said bearing extension.

Claims

2. A pressurized medium motor as recited in claim 1, further comprising two fluid passages for each said opposed piston and cylinder unit, a common pressurized medium supply and a common exhaust for all said units, and means for connecting said units in a predetermined sequence to said supply and exhaust via said two passages.

4. A pressurized medium motor as recited in claim 1 comprising a toothed ring located inside said housing, and at least one pinion wheel on each said eccentric drives meshing with said toothed ring to form a reduction gear.

5. A pressurized medium motor as recited in claim 1 comprising two parallel base plates, bearing pins on said eccentric drives and bearing extensions on said units, and bearing surfaces defined by said plates to receive said bearing pins and bearing extensions so that said eccentric drives can rotate and said units can rock.

7. A pressurized medium motor as recited in claim 1, wherein each opposed piston and cylinder unit consists of a cylinder block defining a bore therein; two oppositely moving pistons located in said bore; a compression spring between said pistons, a rod extension of each said piston of reduced section and extending outwards of said cylinder, and an eccentric-engaging surface on the outward end of each said rod extension.

8. A pressurized medium motor as recited in claim 7, wherein a bearing extension of each cylinder block defines two passages one to supply pressure medium and one for exhaust, said passages being arranged at an angle to the direction of piston moveMent and parallel to one another, said two passages joining one end of a common connecting passage extending along the axis of said bearing extension, the other end of said common passage terminating in the respective cylinder bore, and wherein one bearing plate defines two annular passages as supply or exhaust for said medium, said annular passages being common to all said opposed piston and cylinder units and being in fluid transmitting connection with said passages in said bearing extension.