JPS63163018A - Spherical sliding type joint device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a spherical sliding joint device, and in particular to a spherical sliding joint device that can be suitably used for pillow ball bushes, rods with ball joints, etc. in vehicle suspensions. The present invention relates to an improved structure that advantageously improves its durability and manufacturability.

(Prior Art) Conventionally, as a type of joint device used in vehicle suspensions, etc., a ball portion formed at the tip or axial center of a ball fitting is housed and held in a socket portion of a socket member. A spherical sliding joint device is known in which a member attached to the ball fitting is connected to the socket member in a spherical sliding manner by making the ball part slide spherically within the socket part. .

By the way, in such a spherical sliding joint device,
Conventionally, socket members (
(including the socket part) is formed of a metallic material such as iron, while a sliding member made of a predetermined resin material is disposed on the inner surface of the socket part of the socket member in order to enhance the spherical sliding effect. , a structure in which the outer surface of the ball part of the ball fitting is held by a socket member via the sliding member was generally adopted, but in recent years, it has become popular in vehicles and In order to improve the ring, it has been considered to convert such socket members to resin-based ones.

However, when making such a socket member with resin, for example, the ball part of the ball fitting is placed in a predetermined position in a mold for injection molding the socket member, and then the ball part of the ball fitting is placed in a predetermined position in a cough mold. This is done by injecting a resin material, but during molding, the contact pressure between the two parts is caused by the contraction of the resin material during solidification, and the surface pressure of the socket part against the outer circumferential surface of the ball part. Therefore, the problem of inhibiting the sliding function of the socket member was that it could not be easily achieved by making the socket member resin.

Therefore, the applicant of the present application first filed the patent application No. 15836-1
As No. 2, in the above-mentioned spherical sliding joint device,
The ball part of the ball fitting is covered with an integral elastic composite sliding contact body formed by forming a sliding material layer on the inside in contact with the ball part and a rubber elastic material layer of a predetermined thickness on the outside thereof, and further By forming at least the socket part of the socket member on the outside of the composite sliding contact body by injection molding a predetermined resin, it is possible to prevent the shrinkage of the resin after injection molding of the socket part as described above. We have proposed a spherical sliding joint device in which the generated surface pressure on the outer peripheral surface of the ball part is absorbed by the rubber elastic body of the composite sliding contact body.

(Problem) However, in the spherical sliding joint according to the previous application, the mounting strength of the composite sliding member to the socket part is
For this reason, the injection resin pressure exerted on the outer peripheral surface of the composite sliding contact body during molding of the socket part and the shrinkage of the resin after molding are not considered in particular. If this was done by pressure, there was a risk that the composite sliding body would protrude from the socket part due to the load acting between the ball metal fitting and the socket member.

Therefore, the outer peripheral surface of such a composite sliding contact body is usually subjected to adhesive treatment for the socket portion, but this not only increases the number of man-hours for such adhesive processing, but also increases the number of steps required for such adhesive processing. Because it is difficult to use materials such as polyacetal, which are difficult to adhere to the comb elastic layer, as the material for the socket, the range of application is limited, and there is still room for improvement. be.

(Solution Means) Here, the present invention has been made against the background of the above-mentioned circumstances, and its feature is that the ball part of the ball fitting is connected to the sliding material layer in contact with the ball part. Covering with a composite sliding body integrally formed with a rubber elastic layer of a predetermined thickness on the outside, and further forming a socket part on the outside of the composite sliding body by injection molding of a prescribed resin, In the above-mentioned spherical sliding joint device in which spherical sliding is performed between the ball fitting and the socket part via the composite sliding contact body, the rubber elastic body An engaging portion is provided to restrict relative displacement of the socket with respect to the socket portion.

Note that the engaging portion of such a socket portion is generally formed by inserting the resin material forming the socket portion into a recess provided on the outer circumferential surface of the rubber elastic body, or by inserting the resin material forming the socket portion into a recess provided on the outer peripheral surface of the rubber elastic body. The socket portion is formed by causing the resin material forming the socket portion to protrude so as to cover the socket portion with a predetermined width in the circumferential direction.

(Effect of the invention) Therefore, in the spherical sliding joint device having the structure according to the present invention, the displacement of the rubber elastic body is regulated by the engaging part provided in the socket part. , it is possible to effectively prevent the rubber elastic body (composite sliding body) from protruding from the socket portion when a load is applied to the joint device, and thereby effectively improve the durability of the joint device. Therefore, the sliding function can be stably exhibited.

In addition, in the spherical sliding joint device having such a structure, it is possible to omit the adhesive treatment for the socket portion of the composite sliding contact body, and therefore, the manufacturing man-hour can be effectively reduced, and In view of the adhesion of such a composite adhesive member to the rubber elastic layer, there are no restrictions on the material of the socket portion.

Further, the engaging portion of the socket portion can be formed by inserting the resin material forming the socket portion into a recess provided on the outer circumferential surface of the rubber elastic body, or by moving the end portion of the rubber elastic body in the circumferential direction. If the resin material forming the socket part is formed by protruding so as to cover it with a predetermined width, the engaging part can be formed very easily at the same time as the molding of the socket part. Therefore, such a coupling device can be manufactured with better manufacturability.

(Example) Hereinafter, in order to clarify the present invention more specifically, an example of the present invention will be described in detail with reference to the drawings.

First, FIGS. 1 and 2 show a longitudinal sectional view and a plan view of the main parts of a spherical sliding joint device constructed according to the present invention. In this figure, 10 is a rod formed by injection molding operation of a predetermined synthetic resin material,
The main body portion has an approximately 1)-shaped cross section, and is provided with a socket portion 14 having a spherical concave surface 12 at one end thereof.

On the other hand, in the figure, 16 is a pillow ball fitting having a substantially cylindrical shape, and another member to which the rod IO is to be connected is inserted into the inner hole 18 of the pillow ball fitting, so that it can be attached as one piece. . In addition, the pillow ball fitting 16 includes:
A ball portion 2 having a spherical outer circumferential surface approximately corresponding to the spherical concave surface 12 of the socket portion 14 at its central portion in the axial direction.
0 is integrally formed, and this ball portion 20
is accommodated in the socket portion 14.

Furthermore, a substantially cylindrical sliding member 22 is interposed between the spherical concave surface 12 of the socket portion 14 of these rods 10 and the ball portion 20 of the pillow ball fitting 16 accommodated therein. This sliding contact body 22 is connected to the socket portion 14
A sliding cloth 24 disposed to cover substantially the entire outer circumferential surface of the ball portion 20 housed therein;
It is integrally constituted by a rubber sheet 26 arranged on the outer peripheral surface of 4.

Here, in the rubber sheet 26 constituting the sliding contact body 22, stepped portions 28 as four portions are formed over the entire circumference on the outer circumferential surface of the end portions on both sides in the axial direction. The socket portion 14 includes annular engaging portions 30 that fit into the respective stepped portions 28 of the rubber sheet 26 and sandwich the rubber sheet 26 from both sides in the axial direction. 30 is integrally formed, and at this engaging portion 30.30, the sliding contact body 22
is held in the socket part 14, so that the ball part 20 of the pillow ball fitting 16 is connected to the socket part 14 through the sliding contact body 22 so as to be able to slide spherically.

By the way, in such a spherical sliding joint device,
For example, it will be manufactured according to the method described below.

First, the ball portion 2 of the pillow ball fitting 16 is sewn, etc.
A rubber sheet 26 is formed by injecting a rubber material into a cylindrical sliding cloth 24 having a diameter approximately equal to the outer diameter of 0, which is set in a predetermined rubber mold. As shown, a sliding contact body 22 is provided, in which a rubber sheet 26 having stepped portions 28, 28 is integrally fixed to the outer peripheral surface of the sliding cloth 24 at both ends in the axial direction. Form.

As the sliding cloth 24, any fabric woven using low-friction fibers such as fluororesin fibers or fibers made of a sliding resin such as nylon or polyacetal may be employed. However, in order to improve the adhesion with the rubber sheet 26, it is preferable to use threads made of such low-friction fibers on the inside and threads made of fibers that exhibit good adhesion to rubber materials such as cotton threads. It is preferable to use a material in which the material is woven on the outside. Further, the rubber material forming the rubber sheet 26 is NR, SBR.
, NBR, EPDM, urethane rubber, T1)R, etc., can be selected and employed depending on the conditions of use. Further, the thickness of the rubber sheet 26 will be appropriately determined depending on the load and sliding torque applied to the joint device as a product, but it is usually about 1 to 3 mm thick. Therefore, it is formed to have an inner diameter that is approximately the same as or slightly smaller than the outer peripheral surface of the ball portion 20 of the pillow ball fitting 16. Furthermore, as for the shape of the sliding contact body 22, in addition to the cylindrical shape shown in the example, various shapes such as a polygonal cylindrical shape can be adopted as appropriate. By forming a spherical surface corresponding to the outer circumferential shape of the ball portion 20 of 16, the surface pressure exerted on the ball portion 20 due to the contraction of the resin after molding the socket portion 14 can be made uniform, and good sliding performance can be achieved. desirable in terms of obtaining

Then, with such a sliding contact body 22, the pillow ball fitting 16
While covering the outer peripheral surface of the ball portion 20, the pillow ball fitting 16 is attached to the rod 1 as shown in FIG.
0 is set in a predetermined mold 32.34 for injection molding, and the product cavity 3 of the mold 32.34 is
By injecting a predetermined resin material into the rod 6 and molding the rod 10, the intended spherical sliding joint device is formed. The resin material forming the rod 10 may be a thermoplastic resin such as nylon or polyacetal, or a thermosetting resin such as epoxy or phenol, depending on the conditions of use of the coupling device and the magnitude of the applied load. Any material can be selected without limitation,
However, in order to ensure mechanical strength, glass fibers, carbon fibers, whiskers, etc. can be added to such thermoplastic resins and thermosetting resins to improve their strength. A resin containing a reinforced reinforcing material is preferably employed.

Here, the molds 32 and 34 for molding the rod 10 each include a sliding contact disposed on the outer peripheral surface of the ball portion 20 of the pillow ball fitting 16, as shown in FIG. An annular positioning protrusion 38 is formed that abuts both axial end surfaces of the body 22 and holds the spherical surface of the pillow ball fitting 18 . Then, the resin material forming the rod 10 is applied to the sliding contact body 22.
The stepped portion 28.28 formed in the rubber sheet 26 is inserted into the stepped portion 28.28 so as to cover the outer end surface in the axial direction, and the inserted resin material causes
The engaging portions 30 and 30 that sandwich the sliding body 22 from both sides in the axial direction are integrally formed with the socket portion 14.

By the way, in the spherical sliding joint device having such a structure, the ball portion of the pillow ball fitting 16 is damaged by the injection pressure of the resin material forming the rod 10 and further by the contraction of the resin material during solidification. Blood pressure will be exerted between the outer circumferential surface of 20 and the inner circumferential surface of sliding contact body 22, and this blood pressure may be caused by the elasticity of the rubber sheet 26 itself or by the pillow ball fittings at the axial ends of the rubber sheet 26. The pressure is released by the outward bulge from the gap between the rod 16 and the rod 10, and the pressure is reduced. Therefore, the sliding function is not inhibited by such surface pressure, and a good spherical sliding surface is achieved. Therefore, a joint device having dynamic functions can be obtained.

Therefore, in the spherical sliding joint device having the above-described structure, the sliding member 22 is held between the engaging portions 30 provided on the rod 10 at both end faces in the axial direction, and the rod 10 The sliding contact body 22 when a load is applied between the rod 10 and the pillow ball fitting 16 of the joint device is regulated.
can be effectively prevented from protruding from the socket portion 14, and thereby the durability of such a joint device can be effectively improved, and its sliding function can be stably exhibited.

In addition, in such a spherical sliding joint device, the sliding body 2
Therefore, the number of manufacturing steps can be effectively reduced, and the material of the socket part 14 can be bonded to the rubber sheet 26 of the sliding member 22. There are no restrictions in terms of adhesion.

Furthermore, in this embodiment, since the engaging portion 30 is formed simultaneously with the molding of the rod 10, extremely good manufacturability is achieved.

Incidentally, using a joint device having a structure according to this example, its sliding characteristics etc. were measured, and the values were reported as well as a comparative example.
They are also shown in Table 1 below.

In addition, as a comparative example, a cylindrical sliding body having no concave portion on its outer circumferential surface is held simply by the injection pressure and the contraction pressure during molding of the socket portion disposed on the outer circumferential surface. , a conventional structure was used. Furthermore, as the resin material for the socket portion, glass fiber-containing lipolyasecool resin was used in both the examples and comparative examples.

In addition, in the table, the swinging moment refers to the pillow ball/metal fitting 1.
6 against the socket part 14, and the maximum pullout force is the maximum load acting between the pillow ball fitting 16 and the socket part 14 that such a coupling device can withstand, and the The directional displacement indicates the amount of displacement of the pillow ball fitting 16 with respect to the socket portion 14 when a load of 100 kg is applied in the axial direction thereof.

As is clear from Table 1, the comparative example joint device with the conventional structure can only withstand up to 15 kg of axial load on the pillow ball fitting 16, and can withstand a load of 100 kg. However, in the joint device of this example, the maximum pulling force was significantly improved to 240 kg, and
It is easily understood that the sliding moment is not impaired to the extent that it becomes a problem in use.

As is clear from the above explanation, the rod]0
The engaging portion 30 provided in the socket portion 14 of the sliding contact body 2
It is sufficient that it has the function of regulating the relative displacement of the two, and therefore its specific shape or configuration is not limited.

For example, the engaging portion 3o in the embodiment described above is similar to the sliding contact body 22.
The socket part 14 was formed by inserting the resin material forming the socket part 14 into a stepped part 28 as a recess formed over the entire circumference of the outer peripheral surface of the axial end of the rubber sheet 26 in In addition, it is possible to form recesses in various shapes as shown in FIGS. 6(a) to (d) in the rubber sheet 26, and to fill the resin material into these recesses. Accordingly, it is possible to form an engaging portion in the socket portion 14.

That is, in the sliding contact body 40 shown in FIG. 6(a), a plurality of recesses 42 are formed on the outer circumferential surface of both ends of the rubber sheet 26 in the axial direction. In the sliding contact body 44 shown in (b), a plurality of groove-shaped recesses 46 extending in the circumferential direction are formed on the outer peripheral surface of the rubber sheet 26. In the sliding contact body 48 shown, a plurality of recesses 50 are formed on the outer peripheral surface of the rubber sheet 26.
is formed. In addition, in the sliding contact body 52 shown in FIG. 2D, a plurality of convex portions 54 are formed on the outer circumferential surface of the rubber sheet 26, so that the outer circumferential surface becomes a recess 56. -ing Then, for such a sliding contact body 40, 44, 48, 52, each recess 4 is
By inserting the resin material into 2.46.50.56, engaging portions corresponding to these recesses are formed.

Note that the position and number of recesses provided in the rubber sheet 26 can be arbitrarily selected in addition to the forms illustrated, but the form will depend on the slidability of the ball fitting and the load action. It should be determined taking into account changes in time, etc. In addition, in the examples shown in FIGS. 6(a) to 6(d), all of the sliding bodies are
Although it has a cylindrical shape, it goes without saying that these sliding bodies may be prepared in advance into a spherical shape.

Further, FIG. 7 shows another embodiment of a spherical sliding joint device having a structure according to the present invention. In addition, in the drawings, members having the same structure as those of the embodiment described above are designated by the same reference numerals, and detailed explanation thereof will be omitted.

That is, in such a spherical sliding joint device, a sliding body 58 made of a rubber sheet 26 having no recess on its outer circumferential surface is used, and the sliding body 58 relative to the socket portion 14 is The engaging portions for regulating target displacement are constituted by circumferentially continuous or discontinuous engaging portions 60 that abut against both axial end surfaces of the sliding body 58 with a predetermined width.

In addition, such an engaging portion 60 is constructed by making the abutting surface of the rod 10 in the molding die for the axial end surface of the sliding member 58 smaller than the axial end surface of the sliding member 58, so that the contact surface of the rod 10 is smaller than the axial end surface of the sliding member 58. By causing the resin material forming the rod 10 to protrude, the rod 10 is formed simultaneously and integrally with the molding.

Even in such an engaging portion 60, the sliding body 58
The relative displacement with respect to the rod 10 (socket portion 14) can be effectively restricted, and thereby the various effects described above can all be effectively achieved.

Further, FIG. 8 shows still another embodiment of the spherical sliding joint device according to the present invention. In this embodiment as well, in the drawings, the same members as those in the first embodiment are denoted by the same reference numerals, and detailed explanation thereof will be omitted.

That is, in such a spherical sliding joint device, the sliding body 90 is formed to have a spherical cylindrical shape corresponding to the ball portion 2o of the pillow ball fitting 16, as also shown in FIG. At both ends in the axial direction of the rubber sheet 26 constituting the sliding body 90, protrusions 92,92 extending radially outward in a flange shape are formed continuously or discontinuously in the circumferential direction. And those protrusions 9
2.92 is inserted into the socket portion 14, in other words, the socket portion 14 is formed to sandwich the protrusions 92.92, so that the socket of the sliding contact body 9o An engaging portion 94 that restricts relative displacement with respect to the portion 14 is formed.

In addition, such an engaging part 94 is similar to the above embodiment,
It is formed simultaneously and integrally with the molding of the socket portion 14, and it goes without saying that even in a joint device having such a structure, the various effects described above can be effectively achieved.

By the way, the present invention also applies to a spherical sliding joint device having a structure in which a ball portion formed at the end of a ball fitting is connected to a socket portion (E) of a rod, etc.
A joint device having such a structure, which can be used successfully, will be briefly described below.

That is, in FIG. 10, 62 is a rod formed by an injection molding device of a predetermined synthetic resin material,
Socket part 6 having a spherical concave surface 64 at one end thereof
It is equipped with 6.

On the other hand, in the figure, 68 is a ball joint fitting as a ball fitting to which another member to which the rod 62 is connected is attached, and at one end in the axial direction,
A ball portion 70 having a spherical outer peripheral surface corresponding to the spherical concave surface 64 of the socket portion 66 is integrally formed, and this ball portion 70 is housed within the socket portion 66.

In addition, the spherical concave surface 64 in the socket portion 66 of these rods 62 and the ball joint fitting 6 accommodated therein.
A substantially hemispherical sliding member 72 is interposed between the ball portion 70 and the ball portion 70 of the socket portion 66 so as to cover substantially the entire surface of the ball portion 70 accommodated in the socket portion 66 .

This sliding contact body 72 includes a sliding cloth 74 in contact with the ball portion 70 and a rubber sheet 7 disposed on the outer peripheral surface of the sliding cloth 74.
6 is integrally constructed. In the rubber sheet 76 constituting the sliding body 72, a stepped portion 78 serving as a recess is formed all around the outer peripheral surface of the open end thereof.

On the other hand, an annular engaging portion 80 is provided in the socket portion 66 so as to fit into the stepped portion 78 of the rubber sheet 76 and cover the end surface of the opening of the rubber sheet 76.
are integrally formed, and since the sliding body 72 is held in the socket part 66 by the engaging part 80, the ball part 70 of the ball joint fitting 68 can hold the sliding body 72. The intermediary is connected to the socket/throat portion 66 so as to be able to slide on a spherical surface.

Therefore, in the spherical sliding joint device having such a structure, when a load is applied between the rod 62 and the ball joint fitting 68, the sliding member 72 is prevented from protruding from the socket portion 66. , can be effectively prevented by the engaging portion 80, thereby effectively improving the durability of such a joint device, and stably exhibiting its sliding function. Therefore, the same effects as in the embodiments described above, such as the ability to omit the adhesive treatment for the inner circumferential surface of the socket portion 66 of the socket portion 72, can be effectively exhibited.

Incidentally, since such a spherical sliding joint device can be manufactured in accordance with the same method as in the first embodiment, a description thereof will be omitted.

Also, in the spherical sliding joint device having such a structure, the engaging portion 80 provided in the socket portion 66 of the rod 62
The specific shape or configuration of the device is not limited, and FIG. 1) shows an example as another aspect. In addition, in this example, the same reference numerals are given to the same members as in the previous example, so that
A detailed explanation thereof will be omitted.

That is, in the sliding body 82 of this embodiment, on the outer peripheral surface of the rubber sheet 76 constituting the sliding body 82, a plurality of groove-shaped grooves extending continuously or discontinuously in the circumferential direction are formed. A recess 84 is formed and a socket portion 66
The engaging portions 86 are formed by the resin material forming the fittings entering the recesses 84 during the molding operation.

Further, the socket portion 66 has an engaging portion 88 on the opening end surface of the sliding body 82 that contacts the opening end surface with a predetermined width and restricts its outward displacement. There is.

Although several embodiments of the spherical sliding joint device structured according to the present invention have been described in detail above, these are literal illustrations, and the present invention is to be interpreted as being limited only to such specific examples. It is not something that will be done.

For example, the spherical sliding joint device according to the present invention is applied to members that are to be connected in a spherical sliding manner, and is applied to such members, where a socket portion or a ball portion is formed. , = F' (10,62) and ball fittings (
16, 68), various shapes can be adopted.

Further, it is also possible to improve the strength by embedding a metal member or the like around the socket/7 part or inside the rod.

Furthermore, the ball portion 7 is attached to the end of the ball joint fitting 68.
0, it is not necessary to arrange the rubber sheet 76 of the sliding contact body 72 (82) over the entire outer circumferential surface of the ball part 70 accommodated in the socket part 66; It is also possible to obtain a joint device with a sufficient sliding function by arranging it so as to cover only the side peripheral surface.

In addition, the engaging portion for regulating the relative displacement of the sliding body with respect to the socket portion may be formed integrally with the resin material constituting the socket portion as in the above embodiments.
It is also possible to form it by fixing a regulating member as a separate member to the socket portion.

In addition, although not listed, the present invention can be implemented in embodiments with various changes, modifications, improvements, etc. added based on the knowledge of those skilled in the art, and such embodiments may be incorporated into the present invention. It goes without saying that any of these are included within the scope of the present invention as long as they do not deviate from the spirit.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a spherical sliding joint device as an embodiment of the present invention, and is a view corresponding to the r-I cross section in FIG. 2; FIG. 3 is a perspective view showing a sliding body used in such a joint device, FIG. 4 is a cross-sectional explanatory view showing one step of forming such a joint device, and FIG. It is an enlarged view of the main part. FIGS. 6(a) to 6(d) are perspective views corresponding to FIG. 3, each showing an example of a sliding body suitably used in the joint device according to the present invention. FIG. 7 is a longitudinal sectional view corresponding to FIG. 1, showing a spherical sliding joint device as another embodiment of the present invention. FIG. 8 is a vertical sectional view corresponding to FIG. 1, showing a spherical sliding joint device as another embodiment of the present invention, and FIG. 9 is a perspective view showing a sliding body used in such a joint device. It is a diagram. Moreover, FIG. 10 and FIG. 1) are longitudinal sectional views corresponding to FIG. 1, respectively, showing still another embodiment having a structure according to the present invention. 10.62: Rod 12.64: Spherical concave surface 14.6
6: Socket part 16: Pillow ball fitting 20.70: Ball part 22.4
0.44.48.52.58.72.82.90: Sliding contact body 24.74: Sliding cloth 26.76: Rubber sheet 28.
78 Two-stepped part 30.60.80.86.88.94: Engagement part 42.4
6.50.56.84: Recess 68 - Ball joint fitting 92: Projection Applicant Tokai Rubber Industries Co., Ltd. No. 3rIA Figure 6 (a) (b)

Claims (4)

[Claims] (1) The ball part of the ball fitting is covered with a composite sliding contact body in which a rubber elastic layer of a predetermined thickness is integrally formed on the outside of a sliding material layer in contact with the ball part, and A spherical slide in which a socket part is formed on the outside of the sliding body by injection molding of a predetermined resin, and spherical sliding is performed between the ball fitting and the socket part via the composite sliding body. A spherical sliding type joint device, characterized in that the socket portion is provided with an engaging portion that restricts displacement of the rubber elastic body relative to the socket portion. (2) The engaging portion of the socket portion is formed by inserting a resin material forming the socket portion into a recess provided on the outer peripheral surface of the rubber elastic body. The spherical sliding joint device according to item 1. (3) Claims in which the engaging portion of the socket portion is formed by protruding a resin material forming the socket portion so as to cover the end face of the rubber elastic body with a predetermined width in the circumferential direction. The spherical sliding joint device according to item 1 or 2. (4) The engaging portion in the socket portion is configured such that a circumferential outward protrusion provided at an end of the rubber elastic body is inserted into the socket portion and held. Claims 1 to 3
3. The spherical sliding joint device according to any one of paragraphs.