CN216642230U - Rocker pin ball and engine valve train provided with same - Google Patents

Abstract

The utility model provides a rocker pin ball and an engine valve actuating mechanism with the same, wherein the rocker pin ball is connected to a rocker of an engine in a manner of being rotatably accommodated in a rocker cap, and the rocker pin ball comprises: a shaft portion having one end coupled to the rocker arm; and a head portion that is formed at the other end of the shaft portion and that is accommodated in the rocker cap, wherein a center of a curvature radius of a contact surface of the head portion that contacts the recess portion of the rocker cap is disposed at a position closer to the shaft portion than a portion where a maximum diameter of the head portion is formed.

Description

Rocker pin ball and engine valve train provided with same

Technical Field

The present invention relates to a rocker arm pin ball and an engine valve operating mechanism including the same, and more particularly, to a rocker arm pin ball that transmits the motion of a rocker arm to a valve bridge, and an engine valve operating mechanism including the same that opens and closes an intake port or an exhaust port of an engine.

Background

An engine is a mechanism that converts thermal energy into mechanical energy, and is a reciprocating mechanism that moves a piston by igniting fuel in a combustion chamber and exploding the fuel.

The engine includes a block forming a cylinder, and a cylinder head coupled to the block to seal the cylinder. A piston is reciprocatingly provided in the cylinder, and a combustion chamber into which fuel flows and is combusted is formed between the piston and a cylinder head.

The cylinder head is provided with a valve gear including an intake valve for supplying air to the combustion chamber, an exhaust valve for discharging exhaust gas generated in the combustion chamber, and the like.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a rocker pin ball which reduces the diameter and simultaneously minimizes the contact stress with a rocker cap, and an engine valve actuating mechanism with the rocker pin ball.

The above object of the present invention can be achieved by the following means.

In one aspect, an embodiment of the present invention provides a rocker pin ball connected to a rocker arm of an engine in a manner rotatably received in a rocker cap, the rocker pin ball including: a shaft portion having one end coupled to the rocker arm; and a head portion that is formed at the other end of the shaft portion and that is accommodated in the rocker cap, wherein a center of a curvature radius of a contact surface of the head portion that contacts the recess portion of the rocker cap is disposed at a position closer to the shaft portion than a portion where a maximum diameter of the head portion is formed.

Wherein a radius of curvature of a contact surface of the head portion that contacts the recess of the rocker cap is greater than 0.47 times and less than 0.53 times a maximum diameter of the head portion.

The rocker pin ball includes an upper end portion connected to the other end of the shaft portion, a central portion disposed at a lower end of the upper end portion and forming a maximum diameter of the head portion, and a lower end portion forming a contact surface contacting the recessed portion of the rocker cap.

Wherein the upper end portion includes a first region curved at a first radius of curvature from the other end of the shaft and a second region curved at a second radius of curvature from a lower end of the first region, the central portion is curved at a third radius of curvature from a lower end of the upper end portion, and the lower end portion is curved at a fourth radius of curvature from the central portion to a central axis of the rocker pin ball.

Wherein the fourth radius of curvature has a value greater than the first radius of curvature or even the third radius of curvature.

Wherein the first curvature radius, the second curvature radius and the fourth curvature radius are respectively 1mm, 2.5mm and 4 mm.

In another aspect, an embodiment of the present invention provides an engine valve gear including a rocker arm provided in a cylinder head of an engine, a pushrod connected to one end of the rocker arm, a valve bridge connected to the other end of the rocker arm through a rocker cap and a rocker pin ball, and a valve connected to the valve bridge to open and close an intake port or an exhaust port of the engine, wherein the rocker pin ball includes: a shaft portion having one end coupled to the rocker arm; and a head portion that is formed at the other end of the shaft portion and is accommodated in the rocker cap, wherein a center of a curvature radius of a contact surface of the head portion that contacts the recess portion of the rocker cap is disposed at a position closer to the shaft portion than a portion where a maximum diameter of the head portion is formed.

The effects of the present invention are as follows.

According to the present invention, the diameter of the rocker pin ball is reduced, and the radius of curvature and the vertical length of the head of the rocker pin ball are adjusted, thereby minimizing the contact stress with the rocker cap and improving the durability.

Further, although the diameters of the rocker pin ball and the rocker cap are reduced, a gap between the rocker pin ball and the rocker cap is secured, so that the rotation angle can be maximized.

Drawings

FIG. 1a is a perspective schematic view showing a prior art rocker cap.

FIG. 1b is a perspective view showing the connection of a prior art rocker cap and pin ball.

Fig. 2 is a perspective view schematically showing a combination structure of a rocker arm and a valve according to the prior art.

Figure 3a is a perspective schematic view showing the swing arm cap of the present invention.

FIG. 3b is a schematic cross-sectional view showing the connection of the rocker cap and the pin ball of the present invention.

Fig. 4a to 4c are views showing detailed shapes of a pin ball and a rocker arm cap of the present invention.

Fig. 5a to 5b are views showing detailed shapes of rocker pinballs of the present invention.

Fig. 6 is a graph illustrating calculation of the contact stress between the ball-cup shape.

Fig. 7a is a diagram showing the inclination angle of a prior art pinball.

FIG. 7b is a graph showing the tilt angle of the rocker pinball of the present invention.

Reference numerals

100: rocker cap, 110: body cap, 111: upper body cap, 112: recess, 113: lower body cap, 115: groove, 117: boss portion, 120: a cap, 121: upper cap, 123: protrusion, 125: lower cap, 130: central axis, 200: rocker pin ball, 210: shaft portion, 220: head, 221: overhead end, 222: head center portion, 223: a head lower end portion.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily carry out the embodiments. The utility model may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In addition, portions that are not relevant to the description are omitted in the drawings to clearly describe the present invention, and like reference numerals are given to like portions throughout the specification.

Referring to fig. 2, an engine valve train for opening and closing an intake or exhaust port (not shown) may be provided in the engine. Referring to fig. 2, a rocker arm 1 is connected to a central portion by a support shaft 2 and is provided to a cylinder head 3. When one end of the rocker arm 1 is pushed up by a push rod 4 (or cam), the other end thereof opens the valve by pushing down a valve bridge 6 connected to a valve stem 5, and conversely, when the push rod 4 is lowered, the valve bridge 6 is pushed up by a coil spring 6 of the valve stem 5 to close the valve.

A rocker arm screw 7 capable of adjusting a valve clearance may be fixed to one end of the rocker arm 1 corresponding to the push rod 4 using a nut 8 as a medium. Further, the other end of the rocker arm 1 and the upper portion of the valve bridge 6 may be provided with a ball joint 9 that converts rotational motion into linear motion. The ball joint portion 9 may be composed of a rocker pin ball 1a provided at the other end of the rocker arm 1 and a rocker cap 10 having one end rotatably receiving the rocker pin ball 1a and the other end contacting or fixed to the upper portion of the valve bridge 6.

A head portion formed at a lower portion of a pintle ball coupled to the other end of the rocker arm 1 is surrounded by a rocker arm cap and received, and when the pintle ball reciprocates up and down, a valve bridge 6 connected to the cap reciprocates so that an engine valve connected to the valve bridge 6 can be opened and closed.

Since the reciprocating path of the pin ball and the reciprocating path of the valve bridge 6 are not in the same line with each other, friction occurs with the rotation of the head portion of the pin ball, and contact stress is generated at the contact portion of the head portion.

Conventionally, as shown in fig. 1a, a rocker cap C has an upper portion opened so as to rotatably receive a rocker pin ball 1a, and an upper edge C1 is formed in a circumferential direction with respect to a central axis 13. The rocker pin ball P1 is designed to be as large as possible in order to be able to withstand high contact stresses.

The rocker arm cap needs to be made as small as possible to prevent interference with peripheral components on the engine layout, such as the fuel injector.

In the conventional case, since the rocker cap is formed of steel, it is difficult to manufacture the rocker cap, and there is a problem that durability is deteriorated by repeated operations of the pin ball.

On the other hand, as the rocker cap is made smaller, the rocker pin ball housed inside also needs to be made smaller. However, according to the conventional shape shown in fig. 1b, when the diameter of the rocker pin ball P1 is simply reduced, the contact area with the rocker cap C is reduced, and thus there is a problem that the durability is reduced as the contact stress at the contact portion increases.

In the present invention, a structure of a rocker pin ball and a rocker cap for solving such problems is proposed.

The swing arm cap 100 according to the exemplary embodiment of the present invention will be explained in detail with reference to the accompanying drawings.

Fig. 3a is a schematic perspective view showing a rocker cap of the present invention, fig. 3b is a schematic sectional view showing a connection relationship of the rocker cap and a pin ball of the present invention, and fig. 4a to 4c are detailed shapes showing the pin ball and the rocker cap of the present invention. Describing fig. 4c in further detail, the upper view is a view of the cap viewed from above, and the lower view is a sectional view of the portion a-a.

Referring to fig. 3a to 4c, the rocker arm cap 100 of the present invention includes a body cap 110, a cap 120.

The swing arm cap 100 is formed by inserting a body cap 110 and a cap 120 in close contact with each other in an axially aligned state.

In this case, the body cap 110 and the cap 120 are formed in advance and elastically fixed by an assembling tool (not shown), or the body cap 110 and the cap 120 are press-fixed by a separate pressing tool (not shown) after being trial assembled.

The body cap 110 has a recess 112 in which the head 220 of the stud ball 200 can rotatably contact, and the cap 120 is coupled in such a manner as to surround at least a partial region of the body cap 110 at the upper portion of the body cap 110.

The body cap 110 is formed in the shape of a solid stub (short column) having a circular cross section as a whole.

A groove 115 to which the protrusion 123 of the cap 120 is coupled is provided on the outer circumferential surface of the body cap 110.

According to an exemplary embodiment, the body cap 110 may be divided into upper and lower portions centering on the groove 115. The body cap 110 includes an upper body cap 111 provided at an upper portion of the groove 115 and a lower body cap 113 provided at a lower portion of the groove 115, and a diameter of the upper body cap 111 is formed to be smaller than a diameter of the lower body cap 113.

A boss portion 117 is provided at a lower portion of the body cap 110, i.e., between the lower body cap 113 and the groove 115.

A boss portion 117 is provided along the outer circumference of the body cap 110, and the length of the width of the boss portion 117 corresponds to the difference in diameter of the upper body cap 111 and the lower body cap 113.

When the body cap 110 and the cap 120 are combined, the lower portion of the cap 120 is seated on the boss portion 117. At this time, the lower portion of the cap 120 may be more protruded in a radial direction of the cap 120 than the lower portion of the body cap 110, that is, the outer circumferential surface of the lower body cap 113, and the lower portion of the cap 120 and the lower body cap 113 may be formed with the outer circumferential surfaces of the same diameter without a step difference.

Therefore, according to the present invention, the body cap 110 and the cap 120 are compactly combined, thereby enabling the rocker cap to secure a gap with peripheral components in the engine layout.

On the other hand, according to another embodiment of the present invention, the upper body cap 111 may have the same diameter as the lower body cap 113, in which case the boss portion 117 may not be formed.

The cap 120 is disposed to surround the upper portion of the body cap 110, and is formed in a hollow cylindrical shape having a protrusion 123 coupled to the groove 115 on an inner circumferential surface and an upper cap 121 and a lower cap 125 are opened. In one embodiment, the diameter of the hollow portion 122 formed in the upper cap 121 of the cap 120 may be formed to be 75% or more and 95% or less of the maximum diameter W of the head portion 220 of the rocker pin ball 200 to prevent the later-described rocker pin ball 200 from coming off.

The protrusion 123 provided inside the upper cap 121 of the cap 120 is elastically inserted into the groove 115 of the body cap 110 at the time of assembly to integrate the cap 120 and the body cap 110.

The lower cap 125 of the cap 120 is seated on the boss portion 117 of the body cap 110 when the body cap 110 and the cap 120 are combined.

The cap 120 is made of a different material from the body cap 110.

The cap 120 may be made of Rubber (Rubber), for example, FKM (fluorocarbon) fluororubber having high heat resistance and chemical resistance. The body cap 110 may be made of Steel (Steel).

The cap 120 formed of a rubber material may have a thickness of at least 0.5mm or more to secure strength and rigidity, and hardness (hardness) may be formed in a range of HS 80 ± 8 in shore hardness. In the conventional art, since both the cap and the main body cap are made of the same material, i.e., Steel (Steel), the cap is cracked by physical impact applied during the assembly of the rocker cap, and a notch is formed in the cap to prevent the crack, but the manufacturing cost is increased.

According to the present invention, since the cap is formed of a flexible material, the cap is not cracked even if physical impact is applied during the assembly of the rocker cap, and a gap portion is not required to be formed, thereby not only improving the durability of the rocker cap, but also reducing the manufacturing cost.

As described above, since the body cap 110 and the cap 120 are compactly combined, it is possible to reduce the overall diameter and to enable the rocker arm cap to secure a clearance with peripheral components such as the fuel injector in the engine layout.

The rocker pinball 200 according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the present invention, a shape is proposed that can minimize an increase in contact stress while reducing the diameter of the head 220 of the rocker pin ball 200 and maximize the inclination angle at the time of rotation by reducing the diameter of the rocker cap 100. The specific outer peripheral surface curvature radius and the vertical length of the head 220 will be described below.

Fig. 5a to 5b are views showing detailed shapes of a rocker pinball 200 of the present invention, fig. 6 is a view explaining calculation of contact stress between ball-cup shapes, fig. 7a is a view showing a tilt angle of a conventional pinball 200, and fig. 7b is a view showing a tilt angle of a rocker pinball of the present invention.

Referring to fig. 5a to 5b, a pinball 200 according to an exemplary embodiment of the present invention may include a shaft portion 210 and a head portion 220.

In the rocker pin ball 200, the head 220 may be inserted and coupled through the hollow portion 122 of the upper cap 121 of the cap 120. When the rocker pin ball 200 reciprocates up and down, the shaft portion 210 moves up and down through the hollow portion 122, and the head portion 220 is rotatably coupled to the recess portion 112 of the body cap 110.

One end of the shaft portion 210 may be coupled to the rocker arm 30 to transmit the up-and-down reciprocating motion of the rocker arm to the head portion 220.

The shaft portion 210 may be formed in a substantially rod shape having a constant diameter. A rocker pin ball protrusion 215 for coupling with the rocker arm 30 may be formed at one end of the shaft portion 210, and a head portion 220 may be formed at the other end.

The head portion 220 may be integrally formed at the lower end of the shaft portion 210. The head 220 may be formed substantially in a mushroom shape having a wide top and a narrow bottom.

The head portion 220 may include an upper head end portion 221 adjacent to the other end of the shaft portion 210, a central head portion 222 disposed at a lower end of the upper head end portion 221 and forming a maximum diameter W of the head portion 220, and a lower head end portion 223 forming a contact surface with the recess 112 of the rocker cap 100. However, it should be understood that such distinction is made conceptually with reference to the radius of curvature of the outer peripheral surface, and not based on physically separate regions.

The head portion 220 may have an upper head end 221 formed to extend from a lower end of the shaft portion 210. The diameter of the cephalad end portion 221 may be formed to be curved so as to be gradually larger downward than the diameter of the shaft portion 210. The outer peripheral surface of the headtop end 221 may be curved concavely inward in the radial direction.

The overhead end portion 221 may include a first region 221a bent from the other end of the shaft portion 210 at a first radius of curvature and a second region 221b bent from a lower end of the first region 221a at a second radius of curvature. At this time, the first radius of curvature may be formed smaller than the second radius of curvature. In an exemplary embodiment, the first radius of curvature may be 1mm and the second radius of curvature may be 2.5 mm.

On the other hand, the first region 221a of the head upper end portion 221 may be formed to have a longer vertical length than the second region 221 b. In an exemplary embodiment, the up-down direction length of the first region 221a may be formed to be 0.87mm, and the length of the second region 221b may be formed to be 0.28mm, so that the overall head upper end portion 221 may be formed to have a length of 1.15 mm.

Referring to fig. 3b and 5a, the head upper end 221 of the head 220 of the present invention is formed shorter than a conventional one, so that a sufficient gap with the cap 120 can be secured.

The head central portion 222 of the head portion 220 may be described as being formed extending from the lower end of the second region 221 b. The diameter of the head central portion 222 may be formed to gradually increase downward from the lower end of the second region 221b and then gradually decrease downward after having a height (T in fig. 5 b) having the maximum diameter.

The head center portion 222 may be formed so that the outer peripheral surface is curved in a shape that is convex outward in the radial direction at a third radius of curvature. The third radius of curvature may be the same as the first radius of curvature of the first region 221 a. In an exemplary embodiment, the third radius of curvature may be formed to be 1 mm.

At this time, the up-down direction length of the head central portion 222 may be formed approximately to the length of the head upper end portion 221, and in an exemplary embodiment, when the head upper end portion 221 is formed to be 1.15mm, the up-down direction length of the head central portion 222 may be formed to be 1.16 mm.

The head lower end portion 223 of the head portion 220 may be formed to extend from the lower end of the head central portion 222. The diameter of head lower end portion 223 may be formed to be gradually smaller toward the lower side so that the lowermost end portions of head lower end portions 223 may intersect on the central axis of pin ball 200. The lower end 223 is a portion where the outer peripheral surface directly contacts the recess 112 of the body cap 110. This portion is a portion where contact stress is generated upon rotation, and thus it is necessary to minimize the contact stress of the head lower end portion 223.

For this reason, in the present invention, the outer peripheral surface of the head lower end portion 223 may be curved in a shape convex outward in the radial direction of the fourth curvature half radius. The outer peripheral surface of the lower head end portion 223 may form a contact surface at least a portion of which contacts the recess 112 of the rocker cap 100. The fourth radius of curvature of such a contact surface may be formed to have a value greater than 0.47 times and less than 0.53 times the maximum diameter W of the head 220. The fourth radius of curvature may be formed to be larger than the first or even the third radius of curvature. The fourth radius of curvature may be formed such that its center is higher than a height T forming the maximum diameter W described above. In an exemplary embodiment, the fourth radius of curvature may be formed to be 4 mm.

At this time, the vertical length of the lower end portion 223 may be formed substantially similar to the length of the upper end portion 221 and the central portion 222. In an exemplary embodiment, the length of the lower end 223 may be formed to be 2.36 mm.

As described above, by effectively controlling the radius of curvature of the head part 220, particularly the radius of curvature of the lower end part 223 in direct contact with the body cap, it is possible to minimize an increase in contact stress while reducing the diameter of the head part 220.

On the other hand, the upper end 221, the central portion 222, and the lower end 223 of the head 220 may be formed to be curved to have a specific radius of curvature, and in this case, it is very important to control the vertical length of each of the upper end 221, the central portion 222, and the lower end 223 in order to maximize the inclination angle of the rocker pin ball 200. In the present invention, the vertical length H of the head 220 is preferably set to have a ratio of about 58% of the maximum diameter W.

In the present invention, it was confirmed that the contact stress can be minimized while reducing the diameter of the head 220 in the following manner.

Fig. 6 is a diagram illustrating calculation of contact stress between ball-cup shapes, fig. 7a is a diagram illustrating a tilt angle of a conventional pintle ball 200, and fig. 7b is a diagram illustrating a tilt angle of a rocker pintle ball according to the present invention.

Referring to fig. 6, as for the contact stress between the ball and the cup shape, the radius of curvature r1 of the ball and the radius of curvature r2 of the cup and the contact diameter D are main factors in terms of shape, and the contact stress is calculated by the following [ equation 1 ].

[ mathematical formula 1]

The factors of mathematical formula 1 are as follows.

Pressure of [ sigma ] Hertz

F contact force

A contact area

E modulus of elasticity

V Poisson's ratio

l contact length l ═ π D

r radius of reduction

₁Material of first body (roller tappet)

₂Material of the second body (cam)

Table 1 is a calculation result of contact stress of the rocker arm pin ball 200 of the comparative example 1 (1 a of fig. 5 a) and the comparative example 2 (P2 of fig. 5 a) in which the diameter in the comparative example 1 is reduced by about 20%, and the embodiment of the present invention (in which the Outer diameter is the maximum diameter of the head 220).

[ Table 1]

Referring to [ table 1], when the maximum diameter is reduced by about 20% in comparative example 2 compared to comparative example 1 and the radius of curvature is also reduced to 3.5 accordingly, the contact stress is increased by about 2.2 times. In contrast, in the embodiment of the present invention, when the maximum diameter is reduced by about 20% compared to comparative example 1 while the radius of curvature of the lower end 223 of the head 220 is formed to be 4, it is possible to confirm a result that the contact stress is reduced by about 33% compared to comparative example 2 in which the radius of curvature is also reduced by about 20% as the maximum diameter is reduced only.

Next, as described above, it was confirmed that the inclination angle was maximized while reducing the contact stress by controlling the curvature of the head 220 as shown in fig. 7 a. At this time, the lengths of the respective portions of the head 220 are constituted at a ratio as the following [ table 2 ].

[ Table 2]

a

b

c

d

H/W ratio

Comparative example 2

6％

53％

29％

12％

69％

Examples

0％

50％

25％

25％

58％

Referring to table 2 and fig. 7a, when the diameter and the radius of curvature are reduced by only about 20% as in the above-described comparative example 2, the rocker arm cap can be inclined only about 3 degrees with respect to the pin ball P2, in contrast to fig. 7b, it is confirmed in the embodiment of the present invention that the inclination can be made to about 19 degrees by securing the clearance with the cap 120 by controlling the up-down length of the head 220.

As described above, the pin ball 200 of the exemplary embodiment of the present invention can reduce the overall diameter while minimizing an increase in contact stress corresponding to the reduced diameter rocker cap 100.

Further, when the pin ball 200 rotates, the inclination angle can be maximized by sufficiently securing the clearance with respect to the swing arm cap 100, specifically, with respect to the cap 120.

The above description of the present invention is provided for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified into other specific forms without changing the technical idea or essential features of the present invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. For example, each component described as a single type may be dispersed and implemented, and similarly, components described as dispersed may be implemented in a combined form.

The scope of the present invention is indicated by the appended claims rather than the foregoing detailed description, and all changes and modifications that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Claims (7)

1. A rocker pinball connected to a rocker arm of an engine in a manner rotatably received in a rocker cap, the rocker pinball comprising:

a shaft portion having one end coupled to the rocker arm; and

a head portion formed at the other end of the shaft portion and accommodated in the rocker cap,

the center of the radius of curvature of the contact surface of the head portion that contacts the recessed portion of the rocker cap is disposed closer to the shaft portion than the portion that forms the maximum diameter of the head portion.

2. The rocker pinball of claim 1,

the radius of curvature of the contact surface of the head portion that contacts the recess of the rocker cap is greater than 0.47 times and less than 0.53 times the maximum diameter of the head portion.

3. The rocker pinball of claim 1,

the swing arm cap includes an upper end portion connected to the other end of the shaft portion, a central portion disposed at a lower end of the upper end portion to form a maximum diameter of the head portion, and a lower end portion forming a contact surface to be in contact with the recess of the swing arm cap.

4. The rocker pinball of claim 3,

the upper end portion includes a first region bent from the other end of the shaft at a first radius of curvature and a second region bent from a lower end of the first region at a second radius of curvature,

the central portion is curved with a third radius of curvature from a lower end of the upper end portion,

the lower end portion is curved from the central portion to a central axis of the rocker pin ball with a fourth radius of curvature.

5. The rocker pinball of claim 4,

the fourth radius of curvature has a value greater than the first radius of curvature or even the third radius of curvature.

6. The rocker pinball of claim 4,

the first curvature radius, the second curvature radius and the fourth curvature radius are respectively 1mm, 2.5mm and 4 mm.

7. An engine valve gear comprising a rocker arm provided at a cylinder head of an engine, a push rod connected to one end of the rocker arm, a valve bridge connected to the other end of the rocker arm via a rocker cap and a rocker pin ball, and a valve connected to the valve bridge for opening and closing an intake port or an exhaust port of the engine,

the rocker pin ball includes:

a shaft portion having one end coupled to the rocker arm; and

a head portion formed at the other end of the shaft portion and accommodated in the rocker cap,

the center of the radius of curvature of the contact surface of the head portion that contacts the recessed portion of the rocker cap is disposed closer to the shaft portion than the portion that forms the maximum diameter of the head portion.

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