DE2261578A1 - HYDRAULIC OSCILLATOR - Google Patents

Description

GENERAL SIGNAL CORPORATION

280 Park Avenue

New York, New "York / V.St.A.

Our reference: G 1317

Hydraulic oscillator

The invention relates to a hydraulic oscillator in which the control slide device for the drive element is actuated by flow pressures generated by pump parts are generated, which are controlled by the drive element.

Various hydraulic oscillators of the aforementioned type are known. For example, the following show US patents shown some exemplary embodiments of the aforementioned type: US Pat. No. 2,970,579, 3 007 452, 3 150 566 and 3 540 348.

However, these prior art oscillators are pretty complicated in construction and therefore expensive and do not start up in every position or require additional mechanical

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2,6,578

niche devices to develop this ability.

The invention is directed to providing an improved oscillator of the aforesaid type which relatively is inexpensive to manufacture and in which the control slide device exclusively from hydraulic Ürükken is operated and which is self-starting under all conditions.

According to the invention, the new oscillator has a unitary four-way control slide device in which the control slide by means of a spring or other suitable tensioning parts in one of its two operating positions is pressed and moved by a pair of fluid-operated servomotors that rotate in opposite directions act on the control slide and have unequal areas of action. The smaller servomotor, dei acts on the control slide in the same sense as the clamping means is via a feed pump device with a Working space of the drive element connected, but receives the fluid with the high starting point of the Pump parts only during a time-limited movement of the drive part in one direction. Same way is the larger servomotor with the other working area of the Drive part connected and is connected to the fluid with the high output pressure of a second pump unit also only supplied during a time-limited movement of the drive part in the opposite direction. In addition, the two servomotors are connected to one another via a sprayed overflow. From this it follows advantageous that the hydraulic oscillator according to the invention is self-starting under all operating conditions, regardless of the position in which the drive element is, and that the oscillator according to the invention

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is simple in construction and relatively inexpensive.

In a preferred embodiment of the oscillator according to the invention, the control slide device has a flow-dividing effect and directs a certain one Part of the fluid sent to the oscillator to a reservoir or tank. This is a complete Interruption of the flow rate at the stroke ends of the drive part prevents the pressure peaks or shocks in the conveyor system are minimized. In addition, according to a further advantageous feature, the flow-dividing effect of the control slide can be set will. This advantageously makes it possible to use the Oscillator frequency independent of the amount of fluid supplied so that it is possible to create a use a single oscillator in various applications, even when the fluid volumes are very large are different. Another beneficial feature of the oscillator according to the invention is that the throttling in the cross connection between the servomotors is adjustable. This is useful as the training excessive pressures in the feed pump lines genes can be avoided and that control can be exercised over how much the pump units the Brake the drive element.

Further features, details and advantages of the invention result from the following description of exemplary embodiments based on the drawing. Show in it:

Fig.T is a schematic view of the inventive Oscillator;

2 shows a section through a preferred embodiment example the oscillator; - ^

3 shows a section along the line 3-3 according to FIG and

4 shows a section through a further control slide device for the subject of Fig.2.

In Fig. 1 it can be seen that the improved oscillator has a double-acting drive motor 11 with a cylinder 12 and a reciprocating piston 13, which is connected to the consumer in order to access this either via one or via two equally trained Actuate piston rods 13a and 13b, as well as a pair of opposite working spaces 14 and 15. A four-way control slide device 16 is connected to the working spaces 14 and 15 via flow passages 17 and 18 accordingly connected and serves to alternately pressurize these work spaces or to empty them in the opposite sense. The control slide 16 is moved into the position shown by means of a compression spring and a small servomotor 23 pressed, in which he connects the working spaces 14 and 15 with the feed pump 19 and the reservoir 21, and is moved into the other operating position by means of a larger servomotor 24 in order to establish the connections to the work rooms 14 and 15 to reverse. The motors 23 and 24 are connected to one another via an overflow 25, the one Has throttle point 26 to reduce the flow and each motor is also connected to the delivery line 27 or 28 of a feed pump unit 29 or 31 is connected.

The feed pump unit 29 has a cylinder 32 which is aligned with the cylinder 12 and opens into the working chamber 14, as well as a delivery piston 33 which interacts with the cylinder and which is attached to the drive piston 13 is attached and is designed in size so that there is a radial play of about 0.001 to

0.002 inch (0.03 to 0.05 mm) between the piston and the cylinder wall. Over most of the movement of the piston 13, the delivery cylinder 32 is freely connected to the working chamber 14, so that the servomotor 23 in the is exposed to substantially the same pressure that prevails in the working space * If, however, the drive piston 13 approaches the left end of the path of motion, then penetrates the delivery piston 33 enters the delivery cylinder 32, and the free connection with the working space 14 is interrupted. The leftward movement of the piston 13 thus causes the piston 33 to remove the fluid from the cylinder 32 is displaced out and through the delivery line 27, the pressure being a function of the ratio the effective displacement areas of pistons 13 and 33 are. This ensures that the delivery piston 33 both acts as a control as well as a pump element. The pump unit 31 has cylinder and piston parts 34 and 35, which are identical to the parts used in the pump unit 29, but which are connected to the working space 15 are and serve to! driving a limited Time of the rightward movement of the drive piston 13 to exert a pressure on the servomotor 24.

It should be noted at this point that the pump units 29 and 31 cooperate in addition to their pump function with the throttled overflow 25 to hydraulic To form a buffer for the drive piston 1.3 in order to brake it resiliently in both directions of movement. To this Metal-to-metal contact occurs during normal operation between the stationary and moving parts of the engine 11 prevented.

It should also be noted that the game between each delivery piston 33 and 35 and the associated cylinder 32 or 34 a ring-shaped opening of variable

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Length forms, whereby during the time in which the drive piston 13 comes to rest and reverses its movement two different functions are performed. While the deceleration period, i.e. when a delivery piston moves into its cylinder, throttles the annular one opening the flow from the cylinder to the adjacent one Working space 14 or 15, so that an increased pressure is built up, which is required to control slide valve 16 to move. On the other hand, at the beginning of the subsequent stroke, when the drive piston is accelerated, the annular opening enables a flow from the adjacent one Working space to the delivery cylinder and is used in this way in the adjoining servomotor 23 or 24 a Maintain sufficient pressure on the spool 16 in its new position.

If the pump 19 is at a standstill or the flow of fluid to the oscillator is interrupted in some other way, then the spring 22 presses the control slide 16 into the position shown in the figure. Therefore, once the fluid is pumping is resumed, the working spaces 14 and 15 are immediately pressurized or relieved again. If the piston 13 is in a middle intermediate position at this point in time, as in the figure 1 then it begins to move to the right. Flows during the start of the movement phase a part of the oil conveyed to the working space 14 through a control device to the storage container 21, which from the delivery cylinder 32, the delivery part 27, the overflow 25, the delivery part 28, the delivery cylinder 34, the working space 15 and the flow passage 18 consists. As a result of the throttle point 26, the control flow effects in the servomotor 23 a back pressure that is sufficient in its size to

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to overcome the force generated by the larger motor 24 and to close the control slide 16 in the position shown keep.

When the drive piston 13 approaches its right stroke end, the delivery piston 35 penetrates the cylinder 34, whereby the free connection of the cylinder with the working space 15 is interrupted, and an increased one in the cylinder Itfird creates pressure that is approximately the product of the pressure in the working space 14 and the ratio of the effective area of the piston 13 to the effective area of the piston 35 corresponds. The oil displaced from the cylinder 34 is via the delivery part 28, the overflow 25, the delivery part 27, .und conveyed the delivery cylinder 32 to the working chamber 14, the throttle point 26 now ensuring that the servomotor 24 is exposed to a greater pressure than the servomotor 23. This pressure difference causes in conjunction with the difference between the effective areas of the two servomotors, that the servomotor 24 the control slide 16 moves into its other operating position and that thereby the connections between the feed pump 19 and the reservoir 21 and the workspaces are reversed. During the operation described above, the drive piston 13 is resiliently stopped by the delivery unit 31. Then the drive piston 13 begins to move to the left, since the work space 14 is now relieved and the work space 15 is under pressure.

In the first part of the leftward stroke of the drive piston 13, the pressure in the servomotor 24 decreases, on the one hand, because the fluid flows through the overflow 25 and the conveying part 29 can escape into the storage container 21 and, on the other hand, because the retraction movement of the conveying piston 35 is the volume of the cylinder 34, which is

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motor 24 is connected, enlarged. However, since the speed of the drive piston 13 at this time is relative is small and the length of the annular opening formed by the piston 35 and the cylinder 34 decreases, a pressure flow is generated through the annular opening from the working chamber 15 to the cylinder 34, which is sufficient Has size to generate a low but positive pressure in the servomotor 24. Since the servomotor 23 over the reservoir 21 is relieved, this low pressure is sufficient that the control slide 16 via the servomotor 24 is held in its second position. Of course, there is the connection between the servomotor 24 and the work space 15 free as soon as the delivery piston 35 moves out of the cylinder 34. From this point on is the Servomotor 24 is even exposed to a higher pressure, which depends on the load acting on the drive piston 13 and the size of the throttling at the throttle point 26 is determined.

As soon as the drive piston 13 approaches the left end of its stroke, the delivery piston 33 penetrates the cylinder 32 a spring to brake the drive piston and the oil to bring by the conveying part 27 to the increased previously mentioned pressure. This oil flows to the working space 15 Via the overflow 25, the conveying part 28 and the conveying cylinder 34, and the throttle point 26 consequently ensures that the servomotor 23 has a higher pressure than that in which Servomotor 24 is exposed to the prevailing delivery pressure. The pressure difference is big enough to cover the space difference to balance between the two servomotors, so that the control slide 16 is now pushed back into the position shown will. This process causes the working space 14 to be pressurized and the working space 15 to be depressurized.

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is loaded, whereby the drive piston 13 now begins to move to the right.

During the short time in which the drive piston reverses its direction of movement, and the delivery piston 33 is pulled out of the cylinder 32, the pressure in the servomotor 23 decreases to a low value, which by the amount of oil is determined, which can be conveyed to the servomotor 23 through the annular opening, which is located between the piston 33 and the cylinder 32. Since the servomotor 24 is relieved of pressure via the reservoir 21 is, as soon as the spool 16 returns to the position shown, is that of the servomotor 23 and the compression spring 22 - sufficient force generated to hold the control slide in its position shown.

The drive piston 13 continues its oscillating settlement in the manner described above as long as the oscillator is supplied with oil from the feed pump 19. the The frequency of the oscillator is obviously determined by the amount of oil delivered.

When the drive piston 13 is in the position shown in Figure 2 rest position, in which it is located at the right end of its path of movement or in the immediate vicinity of this end, the influx of pressure fluid dann.verursacht into the working space 14, either no rightward movement of the Drive piston 13 or only such a small movement that the amount of oil delivered by the delivery unit 31 is not sufficient to move the control slide 16 via the servomotor 24. In this case, the servomotor 24 is pressurized by the oil, which is released from the working chamber 14 via the delivery

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cylinder 32, the conveying part 27 and the upper run 25 promoted will. Although some oil through the delivery part 28, the annular, formed by the delivery piston 35 and the cylinder 34 opening, the working space 15 and the flow passage 18 can escape into the storage container 21, the flow restriction in the annular opening is large enough to in the servomotor 24 a sufficient with regard to the difference between the effective areas of the servomotors To create pressure which ensures that the servomotor 24 moves the control slide 16 against the compressive force of the spring 22 and to push the force generated by the servomotor 23 into its second position. When the spool is moves, oil is pumped to the work space 15, the work space 14 is depressurized via the reservoir 21, and the drive piston 13 begins to move to the left. The pressure relief of the working chamber 14 leads to Pressure relief of the servomotor 23 so that the servomotor 24 now only has to overcome the force of the spring 22, to hold the spool 16 in its second position. The control pressure required for this is determined by the oil under delivery pressure is brought from the working chamber 15 through the annular opening in the delivery unit 31 flows to the servomotor 24. As soon as the drive piston 13 moves to the left, the length of the annular opening gradually and thus also the Throttling of the oil flowing through the annular space. As a result, the pressure in the servomotor 24 gradually increases to its maximum value, which is reached when the piston 35 emerges from the cylinder 34 and the flow can take place freely from the working space 15 to this cylinder. From this point on, the oscillator works in the above-described way.

In the case where the drive piston 13 is in

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the leftmost rest position is, the start of the oscillator is in any case problem-free, because the Control slide 16 'is in the position in which the rightward movement of the piston is effected.

Based on the previous explanations, it is now clear that the improved oscillator sets itself in motion in every rest position of the drive piston 13.

It should be noted that at each end of the stroke of the drive piston 13 the flow of the pressure medium from the feed pump 19 is momentarily interrupted. this is a undesirable phenomenon because the pump and delivery system repeats during the life of the oscillator Are exposed to pressure peaks and shocks. In addition, the frequency of the oscillation is directly related to the flow rate of the oil delivered by the pump 19. These Appearance can also be a disadvantage. For example, the oscillator could be used to make crescent shaped To drive rod shears that are pulled by tractors of different sizes. Because big tractors in general Use larger hydraulic pumps than smaller tractors, but the optimal speed for the shear • is independent of their length, the oscillators would have to be manufactured in different dimensions to the to cover the entire range of device dimensions. This naturally leads to an increase in the manufacturing costs. The two aforementioned disadvantages are caused by the in Fig.2 illustrated preferred embodiment of the invention eliminated.

In the embodiment shown in FIG the control slide 16 also serves as a flow divider, the dividing behavior of which can be changed. The tax-

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slide device has a bore 36, which with a central inlet »37 is provided as well as a pair of drainage or return connections 38 and 39 and a pair of intermediate channel openings 41 and 42, the Bore 36 receives a slide body 43 which can be pushed back and forth, with two axially spaced apart arranged and located on the circumference is provided recesses 44 and 45, so that three webs 46, 47 and 48 are formed will. The two operating positions of the slide body 43 are determined by a pair of stops 49 and 51, which are screwed into the housing of the oscillator and in their predetermined position by means of nylon screw caps 52 are held.

In the operating position of the slide body 43 shown in the drawing, the mouth 41 is separated from the drain connection 38 by the web 46 and freely connected to the feed connection 37 via the recess 44, and the mouth 42 is free to the drain connection 39 via the recess 45 connected, while it is throttled with the feed connection 37 along the right edge 53 of the web 47 in connection. In this way, only part of the oil supplied by the pump 19 to the central feed connection 37 is conveyed into the working space 14, and the remainder is discharged into the storage container 21 through the recess 45 and the drain connection 39. The amount of oil thus derived depends on the position of the stop 51, since this determines the size of the feed connection part 37 cooperating with the recess 45. On the other hand, in the second operating position of the slide body 43, the Karial mouth 42 is separated from the outlet connection 39 and is free via the recess 45. Connection to the feed connection 37, and the channel mouth 41 is in free communication with the

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Drain connection 38 via the recess 44 and via the left edge 54 of the web 47 in a throttled connection with the feed connection 37. Therefore, the delivery flow is as before between the storage container 21 and the enlarging one The working space (in this case the working space 15) of the motor 11 is divided, and the one that is branched off to the reservoir The amount of oil is determined by the position of the adjustable limit stop, namely by the stop 49. The two stops 49 and 51 are adjusted while the oscillator is in operation, so that the drive piston 13 moves at substantially the same speed in both directions and that the control slide 16 diverts the part of the incoming flow to the storage container which is necessary to control the desired frequency of oscillation.

It should also be noted that the throttle point 26 in the connecting line 25 between the servomotors 23 and 24 in Figure 2 has the shape of a cock 55, which has three through bores 56, 57 and 58 of different Diameters is provided. The faucet becomes any one of three with a knob 59 through a stop 61 preset positions adjusted to. to rotate the selected through hole in the overflow 25. The adjustability the throttle point 26 is a desirable property in a commercially available oscillator because it a control over the maximum damping pressure and the extent of the braking of the drive piston 13 by means of the Conveyor units 29 and 31 is made possible, so that "with a single oscillator design forces different Size can be achieved.

The adjustable flow-dividing effect, which characterizes the control slide device according to FIG. 2; can

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can also be achieved by the alternative embodiment of the slide body 16 according to FIG. The slider body 143, the Is used in this device, differs from the slide body according to Figure 2 in that it has a has central web 147, the opposite edges 153 and 154 lie in planes with respect to the longitudinal axis of the slide body are inclined in opposite directions. In this embodiment, the throttle degree of the divided Feed channel, which leads from the feed connection 137 to the drain connections 138 and 139 in the two operating positions of the slide body, rather through the rotary position of the bobbin as determined by the axial position of the limit stops 149 and 151. The turning position of the bobbin 14 3 is changed by a knob 6 2, which is attached to the slide body by means of a torque transmitting connection is attached, the connection having a stop 151 with a slot 63 and a in the slot engaging pin 64, the piston of the servomotor 24 and a mandrel 65, the ends of which in corresponding aligned holes in the. engage hollow web 14-8 of the slider body. A stop 66 that goes with a number before. cooperating on the circumference arranged holes in the knob 62, serves to the slide body to hold in its predetermined rotational position lör.bar. The angles of inclination of the edges 153 and 154 are the same, so that a rotation of the knob 62 the same change in the flow distribution in the two operating positions of the control slide 16 causes. Otherwise, the control slide according to FIG. 4 works in the same way as the Control slide according to Fig.2.

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Claims (1)

Sponsorship claims c Λ '■ ■ \ 1 ./Hydraulic oscillator in which the control slide device for the drive element of flow pressures is operated, which are generated by pump parts which are controlled by the drive element, thereby characterized in that a double-acting motor (11) with a drive part (13) is provided is that under the action of the pressure of a pressure medium contained in a working space (14) in a first direction movable and under the action of the pressure of a second opposite working space (15) contained fluid is movable in a second direction, and that a four-way control slide (16) is provided between a first position in which it releases a feed line, which leads from an inlet to the one working ravim (14), as well as a return line leading from the second Working space (15) leads to an outlet, and a second position in which the inlet and outlet connections for the lines and work spaces are reversed, is displaceable, and that a 'compression spring (22) is provided which presses the control slide (16) into the first position, and that a pair of servomotors (23, 24) are provided, which have differently sized pressure areas and act in opposite directions on the control spool, wherein the larger servomotor (24) serves to push the control slide into the second position, and that a first feed pump part (31) with a displacement channel (34) is provided, which with the second ar- - 15 309848/0341 working space (15) and with the larger servomotor (24) is in connection, as well as one of the drive part (13) actuated control part (35) for throttling the connection between the displacement chamber and the Working space (15) during a time-limited movement of the drive part in the first direction, as well a pump part (35) which is driven by the drive part and the fluid during the time limited movement of the displacement chamber displaced to the larger servomotor, and that a second feed pump part (29) is provided with a displacement chamber (32) which is connected to the first working space (14) and the smaller servomotor (23) is connected, as well as a control part actuated by the drive part (13) (33) for throttling the connection between the displacement chamber and the first working space (14) during a time-limited movement of the drive part in the second direction, as well as a pump part (33) which is driven by the drive part and the fluid during the time-limited movement displaced by the displacement chamber to the smaller servomotor, and that a throttled overflow (25, 26) is provided, which connects the displacement chamber of the second feed pump part (29) with the larger servomotor. 2. Oscillator according to claim 1, characterized in that the control slide (16) has a throttled fluid discharge generated, each in the first and second position of the feed connection (37, 137) leads to the respective drain connection. (38, 39, 138, 139). - 16 309848/034 1 3. oscillator according to claim 2, characterized in that g e k e η η. -Draws, that the control slide (16) keeps the drain line cross-section open, and that the throttling the flow through the discharge cross-section when the control slide is moved from the first is reduced to the second layer. r r 4. Oscillator according to claims 2 or. 3, characterized in that to change the flow rate adjustment parts (49, 51, 62-65, 151) are provided through the discharge cross-section. 5. oscillator according to at least one of claims 1 to 4, characterized in that the control slide device (16) has a bore (36), which is divided by five axially spaced inlets, namely a central inlet (37), which forms the feed connection, a pair of duct openings located at the ends of the control slide path (38,39), which form the outlet connections, and one each arranged between the central inlet and an end opening Channel mouth (41, 4 2), which is connected to one or the other work space (14, 15), as well as a slide body (43) which is mounted in the bore so that it can be pushed back and forth and on the circumference with two axially spaced apart recesses (44, 45) is provided so that the slide body (43) is equipped with a central web (4 7) and a pair of end webs (46, 48), and that the parts the control slide device are arranged such that in the first position the free connection of the first intermediate channel mouth (41) with the adjoining end mouth (38) by means of an end web - 17 30 9 848703 A 1 '* (46) is interrupted and the channel mouth via a recess (44) located on the circumference of the control slide the central inlet (37) is in a free connection, and that the second intermediate channel mouth (42) is in free connection with the adjacent end opening (39) via the other recess (45) and along an edge (53) of the central web (47) is connected to the central inlet in a throttled manner and that in the second position, the first intermediate channel mouth (41) via the one recess (44) with the adjacent one End opening (38) is in free communication and with the central inlet (37) along an opposite one Edge (54) of the central web (47) is connected nozzle, and that the free connection of the second temporarily stored channel mouth (42) with the adjacent end opening (39) is interrupted by the other end web (48) and the channel opening (42) over the other recess (45) located on the circumference of the control slide with the central inlet (37) in one free connection. Oscillator according to at least one of Claims 1-5, characterized in that the edges (53, 54) of the opposite end faces of the central web (47) perpendicular to the longitudinal axis of the slide body standing plane, and that the control slide device (16) adjustable stops (49, 51) which cooperate with the slide body and define the first and second positions, and that the setting of the one stop (51) serves to axially and relative to the first end position to move to the channel mouths, so that thereby the flow from the central inlet (37) to - 18 309848/0341 the second intermediate canal mouth (42) along one edge (53) of the central web (47) is changed, and that the setting of the an- ' whose stop (49) is used to axially and relative to the channel mouths to the second end position. push, so that thereby the flow from the central inlet (37) to the first intermediate canal mouth (41) is changed along the opposite edge (54) of the central web (47). 7. Oscillator according to at least one of claims 1-5, characterized in that the edges (153, 154) of the opposite end faces of the central web (147) lie in planes which are in opposite directions with respect to the longitudinal axis of the slide body (143) Directions are inclined, and that the control slide device (16) has adjusting parts (62-66, 151) for rotating the slide body about its longitudinal axis and for locking in a certain position relative to the circumference of the bore, and that the flow restriction from the central inlet (137) to the zx \ ^r nits interposed channel opening (142) in the first position and the throttling of the flow from the central feed is consistently changed to the first temporarily stored channel opening (141) in the second position. 8. Oscillator according to at least one of claims 1-7, characterized in that adjustment parts (55-59) are provided for changing the throttling of the flow through the overflow (25). - ■ - 19 - 309848/0341 9. Oscillator according to claim 8, characterized in that for throttling the flow in the overflow (25) a tap (55) with a plurality of transverse through bores (56-58) in the rotating body is provided, wherein the through bores have different diameters, and that the tap is rotatable in certain positions so that the flow through the overflow by means of a different bore is throttled. 10. Oscillator according to claim 1, characterized in that the double-acting motor (11) has a drive cylinder (12) with a drive piston (13) moving evenly to and fro, which divides the drive cylinder into the opposite working spaces (14, 15), and that each Conveying part (29, 31) has a cylinder (32, 34) which is aligned with the drive cylinder and a smaller one Diameter than this, as well as a delivery piston (33, 35) arranged on the drive piston, which serves both as a control slide part and as a feed pump part, and that the two displacement channels of the two delivery pistons are designed in the same way the dimensions of the delivery pistons are chosen such that there is radial play between the delivery pistons and the cylinder wall results. - 20 - 309848/0341 to Blank page