DE102011122027B3 - Hydrostatic rotary piston motor used as hydraulic motor, has rotor which is dimensioned such that center of diameter of rollers comprises eccentricity to arc center of roller seat, by contact of rollers with rotor external toothing - Google Patents

Abstract

The motor has a rotor (3) having an external toothing (8). The circular arc ends of arc comprising one of the shapes of arc deviating from geometric shape. The points (P1,P2) of intersection of each shape of the circular arc correspond to further different geometric shape having a boundary surface of internal toothing. The rotor is dimensioned such that the center of diameter of rollers (2) has an eccentricity to the center (MKB) of arc of roller seat (7) in the internal teeth of stator (1), based on contact of rollers with the external toothing of rotor.

Description

The invention relates to a hydrostatic rotary piston engine. The invention relates in particular to a hydrostatic rotary piston engine which can be used both as a hydraulic pump, but preferably as a hydraulic motor and in particular as a low-speed torque motor, and has a fixed shaft.

There are many hydrostatic rotary piston engines in the prior art. From the US 4,741,681 A is a hydrostatic rotary engine known. The DE 89 12 593 U1 describes a hydrostatic rotary piston engine.

A hydrostatic rotary piston engine of this type is also from the EP 1 074 740 B1 known. In the rotary piston machine, the rolling bearings of the hydrostatically highly loaded part of the shaft are arranged directly adjacent to a small axial distance in the fixed housing, so that a minimal amount of bending and tooth deformation on the shaft and, accordingly, a maximum amount of pressure and thus torque output can be achieved. Because of this bearing assembly no way to create a 1: 1 rotary connection between the rotary piston acting as a rotor and responsible for the commutation rotary valve, the rotary valve is driven synchronously via a gear transmission from the shaft. In the known embodiment, this gear transmission is an eccentric internal gear, in which the disk-shaped rotary valve itself acts as an eccentric member of this transmission and thus performs an unavoidable orbital movement. Extensive experiments have shown, however, that this idea can not be realized in practice at high working pressures, because the necessary eccentric movement of the rotary valve relative to the fixed control plate does not allow a sufficiently accurate commutation of the machine.

The result is highly fluctuating torque output on the shaft, unsatisfactory volumetric efficiency and high noise because the outer part of the eccentric gear has to work in the high pressure range. The axial compensation of the hydraulic forces acting on the rotary valve by the compensating piston was not optimal due to the eccentric movement of the rotary valve.

Since the teeth of the eccentric drive generate a displacement effect, similar to an internal gear pump, it is unfavorable because of the resulting hydrostatic losses when this displacement occurs in the high pressure part of the machine. With the from the WO 2006/010471 A1 known hydrostatic rotary piston engine is trying to eliminate these shortcomings and at the same time reduce the caused by the orbital movement slightly increased friction at the rotary valve and the manufacturing costs.

In hydrostatic rotary piston engines of the prior art with a centrically mounted continuous shaft, the rotary piston is supported during operation on the shaft. Thus, the previous practice, in machines without a continuous shaft to add the rotary piston with excess in the fixed stator, no longer applicable, since the rotor position is then overridden by the leadership of the rigidly mounted shaft. During operation, these machines show considerable pressure fluctuations in the supply line, resulting in extremely fluctuating output torque, low efficiency and a short service life.

If the external toothing of the rotor to the internal toothing of the stator interference, so the above-mentioned adverse pressure fluctuations occur because the rotor can be moved because of the overdetermination only by considerable force and elastic deformation in the stator.

Sits the rotor, however, with play in the internal teeth of the stator occurs significant leakage and even with small gaps, the function - namely the rotation of the rotor - no longer exists because the shaft guides the rotor and no sealing of the working fluid between the supply and the disposal chambers more exists.

In order to ensure a pressure fluctuation-free function, the geometry of the stator, the rotor, the shaft and the positioning would have to be so accurate in operation without deviation that this can not be produced then.

The object of the present invention is to improve the disadvantages known from the prior art.

The object is achieved by a hydrostatic rotary piston engine according to claim 1.

Advantageous developments are defined in the subclaims.

The invention makes it possible to produce the required individual parts in conventional tolerance positions in machines with centrally mounted continuous shaft.

It is also possible to use rotors in a stator whose largest and smallest external teeth deviate up to 0.1 mm from the theoretical "zero line" (see 1 ).

According to the invention, a hydrostatic rotary piston engine is claimed. The rotary engine has a fixed stator 1 with an internal toothing, wherein the internal toothing rotatably mounted rollers 2 that is in roll seats 7 are arranged. The rotary engine also has a rotor 3 with an external toothing 8th and a centrally mounted shaft 4 on, with the roller seats 7 have a geometric shape having a circular arc KB a) with circular arc ends K ₁ , K ₂ , b) with the radius R _KB and c) a center M _KB and at the circular arc ends K ₁ , K ₂ each one of the shape of the circular arc KB deviating further geometric shape whose distance A from the center M _KB to points P ₁ , P _{2 is} greater than the radius R _{KB of} the circular arc KB, the points P ₁ , P ₂ the intersections of each of the shape of the circular arc KB Deviating further geometric shape with a boundary surface d _{f of} the internal teeth correspond. The rotor 3 is dimensioned such that upon contact of the rollers 2 with the external teeth 8th of the rotor 3 , the center of the diameter of the rollers 2 an eccentricity e to the center M _{KB of} the circular arc KB of the roller seat 7 in the internal toothing of the stator 1 having. D. h., That can be formed due to the eccentricity with working fluid ver- and disposable areas between the roller seat of the stator and the rollers of the internal toothing.

As a stator, the fixed, immovable part of a machine is understood.

The counterpart to the stator is called the rotor, which represents the moving, rotating part of the machine.

A shaft is, in its simplest form, a rod-shaped machine element that is used to pass rotational motions and torques. Shafts, in contrast to axles, transmit torque and are subjected to torsion.

The stator has an internal toothing. The internal gear has rotatably mounted rollers, which in turn are arranged in roller seats of the stator.

The radius of the rollers is inventively smaller than the radius R _{KB of} a central circle with the center M _{KB of} the roller seat. As a result, the role a certain play in the role seat is possible.

The boundary surface d _f corresponds to the root circle of the Statorinnenverzahnung.

A different geometric shape deviating from the shape of the circular arc KB is to be understood as meaning geometries which deviate from the circular shape having the radius R _KB .

Preferably, the deviating from the shape of the circular arc further geometric shape is configured such that it has, for example, a circular geometry with a different radius from the arc, tangentially straight line adjoins the circular arc ends, curved, parabolic or exponential.

Preferably, the distance A at least by 2/100 mm and at most by 3/100 mm larger than the radius of the circular arc executed.

Preferably, a distance Δ _P1P3 between the first intersection P ₁ and the point P _{3 is} provided. Further, a distance Δ _{P2P4 is provided} between the second intersection P ₂ and the point P ₄ . The points P ₃ , P ₄ correspond to the ideal point of intersection of the circular arc with the boundary surface d _{f of} the internal toothing of the stator.

Particularly preferably, the distance Δ _P1P3 , Δ _{P2P4 corresponds} at least to the difference between the distance A and the radius of the circular arc.

Preferably, the arc includes an angle β of greater than 180 °.

Preferably, a distance P ₁ K _{1 is} enclosed by an angle α ₁ and a distance K ₂ P _{2 by} an angle α ₂ . The angles α ₁ and α ₂ are preferably the same size.

The rotor preferably has an external toothing which partially engages in the internal toothing of the stator. Furthermore, the rotor has an internal toothing.

Preferably, the centrally mounted shaft has an external toothing, which partially meshes with the internal toothing of the rotor.

Preferably, an orbital movement with the rotor can be carried out in such a manner that working chambers can be filled with disposable dental chambers between the internal toothing of the stator and the external toothing of the rotor and can be filled between the roller seats of the stator and the rollers of the internal toothing.

By means of a rotary valve, working fluid can preferably be fed to the tooth chambers through supply bores of a distributor plate and, by means of a rotary valve, the tooth chambers can be discharged through disposal bores of a distributor plate working fluid.

As working fluids according to the invention gases or liquids, such as understood. Oils.

Preference is also given to working and disposable areas between the roller seats of the stator and the rollers of the internal toothing.

Particularly preferably, the roller seat of the stator has at least one contact surface on which the roller can rest. Accordingly, the role comes to a right or a left contact surface on the roller seat for concern.

According to the invention, the at least one contact surface can have a circular cross section, a curved cross section, a trumpet-shaped cross section or a straight cross section for receiving the roller.

Preferably, the cross section of the roller seats in the stator - due to the dimensions of the rotor - not completely closed by the roller, so that a gap s between the roller seat of the stator and the roller adjusts. This gap results from the above-mentioned eccentricity in conjunction with the corresponding cross-sectional position of the roller seat and the respective formation of the bearing surfaces. If wrong, d. H. Too small dimensioning of the rotor or without attaching the rotor in the rotary piston engine, however, the gap s would be closed by the roller.

The high-pressure working fluid of the supply chamber can penetrate through the open gap between the roller and its example. Trumpet-shaped seat in the stator and eccentrically sealingly press the roller against its stator seat and a rotor tooth of the external teeth of the rotor.

This allows the Rollenabdichtposition vary within the above conditions and compensate for the existing tolerances and other positional deviations.

It is thus always given a seal between high pressure and low pressure and an occurrence of excess is thus prevented.

With appropriate rotation of the rotor, the gap on the opposite side of the contact surface in the Rollenabdichtposition a.

Upon rotation of the rotor or during a displacement of a rotor tooth of the rotor in a clockwise direction, thus, on the left side between the roller seat of the stator at the one contact surface and the roller, the gap is.

Upon rotation of the rotor or with a displacement of a rotor tooth of the rotor in the counterclockwise direction is on the right side between the roller seat of the stator on the other contact surface and the role of the gap.

An angle φ preferably results from an extended straight line of a tangent contact point of the roller on the roller seat in the stator to the theoretical slot shape of the roller seat.

With particular preference, the angle φ is -15 ° ≤ φ ≤ + 15 °. As a result, the roller just can not slide out of its roller seat, but the eccentricity is large enough to compensate for the existing tolerances and other positional deviations. The gap (s) is always present according to the invention.

Preferably, via a rotary valve as a commutator, the toothed chambers are supplied with the working fluid at a first pressure through the supply bores of the distributor plate.

The expanded working fluid is discharged with a second pressure through the disposal holes in the same way through the distributor plate and the rotary valve again.

In a preferred embodiment, the rollers are tiltably mounted in the roller seat. The relief are designed so that their ends are "spherical". By "early" is to be understood an embodiment in which the two ends of the relief are arched outwards. The rollers are arranged in the rotary engine so that they are limited in the longitudinal direction on the one hand by the bearing flange and on the other hand by the distributor plate, wherein a tilting movement is executable, without causing leaks.

The game, which is due to the length of the role in relation to the stator thickness, allows the role in their seat can tilt to compensate for any angular deviations.

The roller must be able to move as described, but the resulting gaps must still be so small that the volumetric efficiency is maintained.

In addition, it is advantageous for a very constant torque output of the machine, if in the distributor plate, the supply holes of the tooth chambers are arranged on their pitch circle, that the compression between the Zahnkammervolumen at the time when the teeth of the rotor covering the supply holes entirely (mainly left and right of the roller fulcrum) and the smallest resulting chamber volume is kept small.

The teeth of the outer teeth of the rotor never close the supply holes completely and if so, then only for a very short time. Advantageously, the supply holes are arranged close to the internal toothing of the stator, that is to say offset in the direction of the root circle of the internal toothing of the stator to the outside.

Thus, the trapped working fluid in the tooth chamber may additionally utilize the volume of the supply bore in the distributor plate, as far as the shut-off rotary valve, to reduce compression.

This reduces the pressure peaks, significantly reduces the compression energy and smoothes the torque fluctuation. The pressure fluctuations are consequently reduced in the hydrostatic rotary piston engine to a considerable extent.

The invention will now be further illustrated by way of example with reference to the drawings. Hereby shows:

1 a schematic representation of the device according to the invention of a hydrostatic rotary piston engine,

2 a schematic representation of a roller seat,

3 a schematic representation of a detail X from the 1 the device according to the invention and

4 a schematic representation of a detail Y from the 2 the device according to the invention.

The 1 shows a hydrostatic rotary piston engine according to the invention with a centrally mounted continuous shaft ( 4 ), acting as a power output unit with a centric fixed stator ( 1 ) and a rotary piston as rotor ( 3 ).

The stator ( 1 ) has an internal toothing, the rotor ( 3 ) has a partially in the internal toothing of the stator ( 1 ) engaging external toothing ( 8th ) and an internal toothing ( 9 ) on. The wave ( 4 ) meshes with its external teeth ( 10 ) partially the internal toothing ( 9 ) of the rotor ( 3 ).

The rotor ( 3 ) is arranged to perform an orbit movement such eccentric and dimensioned accordingly that with working fluid ver and disposable tooth chambers between the inner teeth of the stator ( 1 ) and the external teeth ( 8th ) of the rotor ( 3 ) form.

The teeth of the internal toothing of the stator ( 1 ) are considered roles ( 2 ) educated. About the rotary valve ( 6 ) as a commutator is the tooth chambers through the supply holes of the distributor plate ( 5 ) supplied the working fluid with the pressure (p ₁ ).

The expanded working fluid is at the pressure (P ₂ ) through the disposal holes in the same way through the distributor plate ( 5 ) and the rotary valve ( 6 ) discharged again.

The division high pressure - low pressure is likewise in 1 shown along the vertical machine centerline. Due to its eccentric position, the rotor ( 3 ) by the resulting pressure force (Fp) of the working fluid in the tooth chambers with high pressure around the roller pivot point with the supporting force (FS) with its internal toothing against the external toothing of the shaft ( 4 ) and generates the shaft torque forming force (FM).

In 2 is a schematic representation of a roller seat shown. The roller seats ( 7 ) has a geometric shape that includes a circular arc (KB) with arc ends (K ₁ , K ₂ ), radius (R _KB ), and center (M _KB ). An angle (β) of the circular arc is selected here with 195 °. The arc ends at points (K ₁ ) and (K ₂ ). The points (K ₁ ) and (K ₂ ) lie on a circular line (d ₀ ), all center points (M _KB ) of the roller seats ( 7 ) connects.

At the circular arc ends (K ₁ , K ₂ ), a straight line connects on both sides in such a way that the circular arc ends are extended tangentially in a straight line. At the selected angle (β) of <180 ° of the circular arc and the adjoining straight line, a geometric shape sets in, which is referred to below as "trumpet-shaped".

The rectilinear extension extends from the circular arc ends (K ₁ , K ₂ ) to the points (P ₁ , P ₂ ). The points (P ₁ , P ₂ ) correspond to the points of intersection of the respective other geometric shape deviating from the shape of the circular arc (KB) (in this case the straight line) with a boundary surface (d _f ) of the internal toothing. The distance (A) from the center (M _KB ) to points (P ₁ , P ₂ ) is greater than the radius (R _KB ) of the circular arc (KB).

The points (P ₃ , P ₄ ) correspond to the ideal point of intersection of the circular arc (KB) with the boundary surface (d _f ) of the internal toothing of the stator (FIG. 1 ). A distance (Δ _P1P3 ) between the point (P ₁ ) and the point (P ₃ ) and a distance (Δ _P2P4 ) between the point (P ₂ ) and the point (P ₄ ) is present accordingly.

In the present case, the distance ( _ΔP1P3 , _ΔP2P4 ) is at least the difference between the distance (A) and the radius (R _KB ) of the circular arc (KB).

Further, an angle (α ₁ ) between the intersections (P ₁ , P ₂ ) and the circular arc ends (K ₁ , K ₂ ) is included. The angle occurs on both sides and amounts to approx. 25 ° each.

In 3 is a schematic representation of a detail X from the 1 the device of the invention shown

The role ( 2 ) has a diameter which is dimensioned so that the roller ( 2 ) in your seat in the respective stator ( 1 ) has a suitable game. The roller seat ( 7 ) in the stator ( 1 ) is as in 2 represented, executed "trumpet-shaped". The rotor ( 3 ) is dimensioned such that when the rollers ( 2 ) in contact with the tooth tip circle of the rotor ( 3 ), the center of the roller diameter is eccentric (e) in front of the center of the roller seat diameter and the roller outer diameter is not the trumpet opening of the roller seat (Fig. 7 ) so that a suitable gap (s) always remains. The length of the rollers ( 2 ) has a suitable play to the stator thickness and has the same dimensions as the rotor thickness.

The high pressure working fluid of the supply chamber may pass through the open gap (s) between the roller (11). 2 ) and its trumpet-shaped seat in the stator ( 1 ) and the role ( 2 ) eccentrically sealing against its stator seat (sealing position Pk2) and the rotor tooth (Pk1).

As a result, the roller sealing position (Pk) can vary within the abovementioned conditions and compensate for the existing tolerances and other position deviations.

This is always a seal between high pressure and low pressure and an occurrence of oversize is thereby avoided.

By using a suitable toothing brings the rotor ( 3 ) an additional force on the roll ( 2 ), which pushes them into their sealing position (Pk ₂ ) in a stator seat, since the roller ( 2 ) is eccentric (e) in front of its theoretical "Abrollpostion" in the stator seat.

The geometry of the contact surface ( 11 . 12 ) in the roller sealing position (Pk2) in the stator is "trumpet-shaped". A corresponding shape can z. B. done by a curve, by arcs, by straight lines or other geometric shapes. The execution is to be executed left and right (because of left and right rotation of the machine).

In the embodiment shown as a straight line, a Tangentenberührpunkt the roller seat ( 7 ) in the stator ( 1 ) and the remaining distance from this to the root circle of the stator internal teeth is performed as a straight line.

The deviation of the straight line from a theoretical slot shape forms the angle (φ). According to the 3 respectively. 4 (Detail Y) is the tangent contact point (TP) on the roller seat ( 7 ) in the stator ( 1 ) at the height of the intersection of the pitch circle (d ₀ ) of the Statorrollensitze with the circumference of the roller seat ( 7 ) in the stator ( 1 ), wherein the angle (φ) between -15 ° and + 15 ° is executed. The pitch circle (d ₀ ) runs through all centers (M _KB ) of the roller seats.

This allows the role ( 2 ) just not (yet) to slip out of her seat. However, the possible eccentric position (e) is sufficiently large to compensate for the existing tolerances and other position deviations. The gap (s) is always present. (As an alternative to the straight line with the angle (φ) is also a curve and a circular arc in 4 shown.)

As described above, due to the length of the reels ( 2 ) in relation to the stator thickness that the corresponding role ( 2 ) in their seat ( 7 ) can tilt to compensate for any angular deviations.

The role ( 2 ) must be able to move, but the resulting gaps (s) must still be so small that the volumetric efficiency is nevertheless maintained.

According to 1 it is advantageous for a very constant torque output of the machine when in the distributor plate ( 5 ) the supply bores ( 13.1 . 13.2 . 13.3 , etc.) of the tooth chambers are arranged on their pitch circle, that the compression between the Zahnkammervolumen at the time when the teeth of the rotor ( 3 ) completely cover the supply bores and keep the smallest arising chamber volume small.

The teeth of the outer toothing ( 8th ) of the rotor ( 3 ) do not completely close the supply holes, leaving a small gap. Thus, the trapped working fluid (VT) in the tooth chamber may additionally increase the volume of the supply bore in the distributor plate (FIG. 5 ), to the shut-off rotary valve ( 6 ), to reduce the compression, so that the pressure fluctuations are minimized.

LIST OF REFERENCE NUMBERS

1

stator

2

role

3

rotor

4

wave

5

distribution plate

6

rotary valve

7

rolling seat

8th

External toothing of the rotor

9

Internal toothing of the rotor

10

External toothing of the shaft

11

contact area

12

contact area

13.1

supply hole

13.2

supply hole

13.3

supply hole

KB

arc

A

distance

K ₁

Arc end

K ₂

Arc end

R _KB

Arc radius

M _KB

Arc center

P ₁

intersection

P ₂

intersection

P ₃

Point

P ₄

Point

R '

radius

_ΔP1P3

distance

Δ _P2P4

distance

VT

working fluid

p ₁

print

p ₂

print

s

gap

e

eccentricity

PK ₁

rotor tooth

PK ₂

Rollenabdichtposition

FP

thrust

FM

Force from shaft torque

FS

supporting force

TP

Tangentenberührpunkt

d ₀

Partial circle of the stator roller seats

d _f

Boundary surface of the internal toothing

Claims (14)

Hydrostatic rotary piston engine comprising - a fixed stator ( 1 ) with an internal toothing, wherein the internal toothing rotatably mounted rollers ( 2 ), which are in roll seats ( 7 ), - a rotor ( 3 ) with an external toothing ( 8th ) and - a centrally mounted shaft ( 4 ) wherein the roller seats ( 7 ) have a circular shape (KB) a) with circular arc ends (K ₁ , K ₂ ) b) with the radius (R _KB ) and c) a midpoint (M _KB ) and - at the circular arc ends (K ₁ , K ₂ ) each having a different from the shape of the circular arc (KB) other geometric shape whose distance (A) from the center (M _KB ) to points (P ₁ , P ₂ ) is greater than the radius (R _KB ) of the circular arc (KB), wherein the points (P ₁ , P ₂ ) correspond to the intersections of the respective other geometric shape deviating from the shape of the circular arc (KB) with a boundary surface (d _f ) of the internal toothing, wherein the rotor ( 3 ) is dimensioned such that upon contact of the rollers ( 2 ) with the external toothing ( 8th ) of the rotor ( 3 ), the center of the diameter of the rollers ( 2 ) an eccentricity (e) to the center (M _KB ) of the circular arc (KB) of the roller seat ( 7 ) in the internal toothing of the stator ( 1 ) having. Hydrostatic rotary piston engine according to claim 1, wherein the other of the shape of the circular arc (KB) other geometric shape is designed such that it - has a circular geometry with a circular arc (KR) different radius (R '), - tangentially rectilinear to the Circular arc ends (K ₁ , K ₂ ) adjoins or - is curved Hydrostatic rotary piston engine according to one of the preceding claims, wherein the distance (A) at least by 2/100 mm and at most by 3/100 mm larger than the radius (R _KB ) Hydrostatic rotary piston engine according to one of the preceding claims, _comprising - a distance (Δ _P1P3 ) between the point (P ₁ ) and the - point (P ₃ ) and - a distance (Δ _P2P4 ) between the point (P ₂ ) and the point ( P ₄ ) wherein the points (P ₃ , P ₄ ) the ideal intersection of the circular arc (KB) with the boundary surface (d _f ) of the internal toothing of the stator ( 1 ) correspond. Hydrostatic rotary engine according to claim 4, wherein the distance (Δ _P1P3 , Δ _P2P4 ) at least the difference between the distance (A) and the radius (R _KB ) of the circular arc (KB) corresponds. Hydrostatic rotary piston engine according to one of the preceding claims, wherein the circular arc (KB) forms an angle (β) of 180 °. Hydrostatic rotary piston engine according to one of the preceding claims, wherein a distance (P ₁ K ₁ ) an angle (α ₁ ) and a distance (K ₂ P ₂ ) forms an angle (α ₂ ). Hydrostatic rotary piston engine according to one of the preceding claims, wherein - the rotor ( 3 ) partially into the internal toothing of the stator ( 1 ) engaging external toothing ( 8th ) and the rotor ( 3 ) an internal toothing ( 9 ) and - the shaft ( 4 ) an outer toothing ( 10 ), which partially the internal toothing ( 9 ) of the rotor ( 3 ) combs. Hydrostatic rotary piston engine according to claim 8, wherein the cross section of the roller seats ( 7 ) in the stator ( 1 ) not completely from the role ( 2 ) is closed, so that a gap (s) between the roller seat ( 7 ) of the stator ( 1 ) and the role ( 2 ). Hydrostatic rotary piston engine according to claim 9, wherein with appropriate displacement of a rotor tooth (PK ₁ ) of the rotor ( 3 ) the gap (s) on the opposite side of a contact surface ( 11 . 12 ) is adjustable. A hydrostatic rotary piston engine as claimed in any one of the preceding claims, wherein an angle (φ) of an elongated straight line of a Tangentenberührpunkts (TP) of the roll ( 2 ) on the roller seat ( 7 ) in the stator ( 1 ) to the theoretical slot shape of the roller seat ( 7 ). A hydrostatic rotary piston engine according to claim 11, wherein for the angle (φ), -15 ≤ φ ≤ + 15 °. Hydrostatic rotary piston engine according to one of the preceding claims, wherein supply bores ( 13.1 . 13.2 . 13.3 ) not completely from the rotor ( 3 ) are coverable. Hydrostatic rotary piston engine according to one of the preceding claims, wherein the rollers ( 2 ) in the roller seat ( 7 ) are tiltably mounted and formed crowned at their ends.

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