DE2152641A1 - Damping device for a hydraulic pressure piston - Google Patents

Description

PATENT LAWYERS

DR.-ING. BY KREISLER DR.-ING. SCHÖNWALD 2152641 DR.-ING. TH. MEYER DR. FUES DIPL.-CHEM. ALEK VON KREISLER

DIPL.-CHEM. CAROLA KELLER DR.-ING. KLOPSCH

DIPL.-ING. SELTING COLOGNE 1, DEICHMANNHAUS

Oct. 21, 1971 Sch-DB / ls

Massey-Perguson Services N.V.

Abraham de Veerstraat JA, Curacao (Netherlands Antilles)

Damping device for a hydraulic pressure piston

The invention relates to hydraulic pressure pistons, in particular devices for damping their piston movement at the end of each stroke.

It is often desirable that the piston of a hydraulic pressure piston unit soften towards the end of its stroke is stopped, and that he is not prevented by the damping device from getting with the greatest possible To start acceleration in the opposite direction.

According to the invention, a damping device for a hydraulic pressure piston is characterized by a ring and a tapered portion that joins the ring to form a resizable opening

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cooperates between the two parts and by first and second pressure piston parts which can be brought closer to one another during the end stroke movement, the ring being attached to the first pressure piston part and the tapering part being attached to the second pressure piston part and either the ring or the tapering part being provided on the respective pressure piston part that between himself and his pressure piston support part a flow occurs when the flow is in one direction, while it is changed ψ when the flow is in the other direction.

It is advantageous that the tapered part is carried by the piston, and that the ring of the Piston cylinder is worn and inserted into a recess, which its sealing inclusion in the recess allows when the flow from the cylinder passes behind the variable-size opening or from it lifts off the seat and allows the flow both through the opening and through the recess in the cylinder, when the flow is opposite.

It is useful that the ring is secured by a snap ring in the recess and on its contact surface is crowned with the snap ring so that the flow is not restricted.

In a further embodiment of the invention, a hydraulic pressure piston is proposed which is marked is by a cylinder, a piston and a piston rod axially displaceable in the cylinder; by a bearing between the piston rod and the cylinder; by an annular passage between an end portion of the bearing and the piston rod, one end of the passage

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let opens into the cylinder chamber and faces the piston, while its other end is connected to a fluid inlet of the cylinder through a countersunk Annular recess in the end face of the bearing at the mouth of the passage, the recess in the mouth the passage represents a radial seat; by a first ring in the recess, which radially after inside partially protrudes into the ring passage and a ring opening between the ring and the piston rod forms; by a second ring, which can be moved into the opening with the piston rod, with adjacent ones Surfaces of the rings are beveled relative to one another, so that the passage through the opening is gradual The further the second ring pushes into it and through an annular gap between the outer one becomes smaller Peripheral surface of the first ring and the recess, wherein the first ring is axially limited in the recess is movable, so that during operation - when the second ring moves against the first ring - the latter is pressed against the seat by fluid pressure and, when the piston has finished its stroke movement, the opening is essentially closed by the second ring and the piston is just beginning a stroke movement, the fluid pressure through the annular passage lifts the ring from the seat, so that some fluid through the annular gap into the Cylinder chamber can enter.

The invention also relates to a ring bearing for use between the piston rod and the cylinder of a hydraulic pressure piston, characterized by a bore located in the outer end part of the bearing for a piston rod; through a larger diameter hole at the inner end of the bearing, to the one Feed for hydraulic pressure fluid can be connected; through a countersunk recess on the inside

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End face of the bearing that has a radial seat between the peripheral wall of the recess and the peripheral wall of the Represents larger diameter bore; by one in the recess against the seat and axially away from it movable ring, the diameter of which is larger than that of the bore, and which has a smaller inner diameter than has the larger bore; through an annular gap between the outer peripheral surface of the ring and the Scope of recess; by a snap ring limiting axial movement of the ring away from the seat in the circumferential wall of the recess, and by crowning in the face of the closest to the snap ring Ring, the crowning between the two parts form slots, one end of which in each case into the annular gap opens.

The invention is based on one in the single figure The example shown in longitudinal section explained in more detail.

A pressure piston 1 consists of a cylinder 2 in which a piston 3 can be displaced in a fluid-tight manner. The piston 3 is designed in two parts. The conveying part 4 carries a wear ring or wear ring on its outer circumferential surface. a series of metal inserts 5 that make the piston 3 in guide the cylinder 2 and the rear part 6 is provided with circumferential grooves 7, embedded in the seals 8 are. A piston rod 9 carries a flange ring or a sleeve 10, the outer surface 11 of which is in the Piston 3 tapers inwards towards piston rod 9 in the opposite direction. Parts 4 and 6 of the piston 3 and a flange of the sleeve 10 are pushed onto a neck portion 9A of the piston rod 9 and are between a nut 13 screwed onto a threaded end of the neck section 9A and a school

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ter 12 of the piston rod 9 held.

A bearing 14 through which the piston rod 9 is passed is, has substantially cup shape and is held in position at the end of the cylinder 2 in that it by a nut 16 engaging with a threaded end part 17 of the bearing firmly against a stop ring 15 is pulled and rests against the end of the cylinder 2. To prevent leaks there are between the bearing 14 and the cylinder 2 O-rings 18. The bearing 14 is equipped with seals I9 which press against the piston rod 9 and are held by a snap ring 20.

A circumferential passage 21 is located between the O-rings 18 provided, which via channels 23 with an annular passage or a chamber 22 between the bearing 14 and the piston rod 9 is in communication. The corridor 21 is with connected to a passage 24 of the cylinder 2, the passage 24 being connected to a line 25.

The bearing 14 has at its inner axial end, namely at its radial inner circumference at the inner end of the annular passage or the chamber 22 has a countersunk ring seat or a recess 26. In the axial A groove 27 is provided on the wall of the recess 26, into which a snap ring 28 is inserted. One with a game matching axially movable ring 29 is held in the recess by means of a snap ring 28. The ring At the end facing away from the piston 3, 29 has a series of inclined crowns on its radial outer surface 30, which come to rest against the snap ring 28 under conditions to be described. The radially inner surface of the ring 29 is beveled at 5I. The back of the ring 29 is flat and

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partially protrudes over the mouth or the inner end of the passage or the chamber 22 radially inward and can, under certain circumstances to be explained, sit on the radial wall 32 of the recess 26. The cylinder chamber between the piston 3 and the bearing 14 is denoted by the number 33. The outer or The free end of the sleeve 10 also shows a bevel 34, through which the hydraulic shock at the transition dl * bevel 31 is reduced.

^ The mode of operation of the damping device is described below described.

Assuming that the bearing 14 is stationary and the piston 3 is moving in its direction, fluid arrives from chamber 33 into chamber 22 and passes through channels 23, passage 21 and passage 24 into the conduit 25 a.

In the position shown, there is no impermissible restriction of the flow, but it does push As the piston 3 moves further, the beveled Sleeve 10 into the ring 29 and a throttle opening builds up between them, which leads to a pressure increase leads in chamber 33. This increase in pressure tends to slow down the piston and forces the ring 29 firmly on ciio radial wall 32, so that a positive flow around the outside of the ring 29 between the latter and the bearing 14 is prevented and a flow is only guaranteed through the opening. "The sleeve 10 closes the opening gradually with further movement to the right and the piston 3 becomes progressive, relatively soft way slowed until it comes against the bearing 14 to the plant.

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If desired, the piston 3 in the drawing to move to the left, is through the line 25 * the passage 24 and the channels 23 high pressure fluid in the Chamber 22 introduced. The high pressure acts on the ring 29, removes it from the wall 32 and pushes the Crownings 30 against the snap ring 28 so that the fluid around the outside of the ring 29 and in the slots between the crowns 30 downwards can flow into the chamber 33. In addition, the fluid passes through the opening formed by the ring 29 and the sleeve 10, although this initially narrows and gradually expands until the sleeve 10 closes away from the ring 29.

In the embodiment mentioned, it is advantageous that the sleeve 10 and the ring 29 can be produced very easily and inexpensively. Since they are not exposed to high stresses that would make their manufacture from more expensive material necessary, they can consist of cheap material, which increases their economic efficiency. Another advantage is that the pressure pistons for end-stroke damping can be adapted to their desired performance by simply selecting a ring 29 and a conical sleeve "0 of suitable dimensions .. the test and be ^ tried This is very easy durchührbar by l6 and acceptance of the ring 15 the camp lh after unscrewing the nut is pulled out • draufhin the snap ring 26 may be removed so; ate the ring 29 by a ring can be replaced with slightly different dimensions and the bearing can be reinstalled in the cylinder .

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The invention comprises the use of a floating sleeve in the bearing and a ring fixed on the piston, Alternatively, the floating part sits on the piston when the fluid is supplied through the piston rod.

In a further embodiment of the invention, the inclined surface can be an inner surface of revolution with which the outer circumferential surface of the ring cooperates to form the variable opening.

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Claims (9)

Expectations 1.) Damping device for a hydraulic pressure piston, marked by a Ring and a tapered part that joins the ring to form a resizable opening cooperates between the two parts and can be brought closer to one another by the first and second during the final stroke movement Pressure piston parts, the ring on the first pressure piston part and the tapered part on the second plunger part is attached and either the ring or the tapered part on the respective Plunger part is provided so that between itself and its plunger support part in the case of a flow in one direction, a flow occurs, whereas in the case of a flow in the other direction is prevented. 2. Apparatus according to claim 1, characterized gekennzei chnet that the tapered Part (10) is carried by the piston (3) and that the ring (29) is carried by the piston cylinder (2) and is inserted into a recess (26) which allows its sealing storage in the recess, when the flow from the cylinder passes behind the variable opening or from the seat lifts off and allows the flow both through the opening and through the recess in the cylinder, when the flow is opposite. 3. Device according to claim 2, characterized in that that the ring (29) through. a snap ring (28) secured in the recess (26) and at its contact surface with the explosive - 10 209819/0629 ring is designed to be cremated so that the flow does not is restricted. 4. Apparatus according to claim 1, 2 or 3 * thereby characterized in that it is built into a hydraulic pressure piston. 5 · Hydraulic pressure piston, marked by a cylinder (2), a piston (3) and a piston rod (9) axially displaceable in the cylinder; P through a bearing (14) between the piston rod (9) and the cylinder (2); through a ring passage (22) between an end portion of the bearing and the piston rod, one end of the passage into the cylinder chamber (33) opens and is opposite the piston, while its other end with a fluid inlet (24) of the cylinder (2) is connected; through a countersunk ring recess (26) in the end face of the bearing (14) at the mouth of the passage (22), the recess having a radial seat in the mouth of the passage represents; by a first ring (29) in the recess (26), the radially inward partially in the annular passage (22) protrudes and forms an annular opening between the ring (29) and the piston rod (9); by a second ring (10) which can be moved into the opening with the piston rod (9), wherein adjacent surfaces of the rings are beveled relative to each other so that the passage through the The opening becomes gradually smaller the further the second ring (10) pushes into it and through one Annular gap between the outer circumferential surface of the first ring (29) and the recess (26), wherein the first ring is axially movable to a limited extent in the recess, so that during operation - if the second ring moves against the first ring, the latter being pressed against the seat by fluid pressure 209819/0629 - left - and, when the piston has finished its stroke movement, the opening of the second ring is essentially is closed and the piston is just beginning a reciprocating motion, the fluid pressure through the annular passage (22) lifts the ring (29) off the seat so that some fluid flows through the annular gap into the cylinder chamber (33) can occur. 6. Hydraulic pressure piston according to claim 5 »thereby characterized in that the axial movement of the first ring (29) in the direction away from the seat is limited by a snap ring (28) in the peripheral wall of the recess, and that the snap ring (28) facing contact surface of the first ring (29) has crownings (jJO), which between the Both rings form slots through which fluid can pass when the first ring is deposited against the snap ring can. 7. Hydraulic pressure piston according to claim 5 or 6, characterized in that the recess (26) and the first ring (29) are provided in the piston (3), and that the second ring (10) is on the bearing (14) and the fluid supply passes through the piston rod (9). 8. Hydraulic pressure piston according to claim 5, 6 or 7, characterized in that the first ring is cylindrical and the outer surface of the second ring is beveled. 9. Ring bearing for use between the piston rod and the cylinder of a hydraulic pressure piston, gekennzei chnet by a bore located in the outer end part of the bearing for a piston rod; through a larger diameter hole 209819/0629 - 12 - at the inner end of the warehouse to which a feed for hydraulic pressure fluid can be connected] through a countersunk recess on the inner end surface of the Bearing ,, which has a radial seat between the peripheral wall represents the recess and the peripheral wall of the larger diameter bore; by one in the Recess against the seat and away from this axially movable ring, the diameter of which is greater than that of the bore, and which has a smaller inner diameter than the larger bore; - through P an annular gap between the outer circumferential surface the slope and extent of the recess; through a limiting the axial movement of the ring away from the seat Snap ring in the circumferential wall of the recess and by crowning in the snap ring nearest end face of the ring, with the crowning forming slots between the two parts, one end of which opens in each case in the annular gap. ORfGfNAL fNSPECTED 209819 / Q629