JPH0449951B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Applications Glass and/or mineral fibers are widely used for thermal and/or sound insulation. In glass fibers, the common practice is to cut continuous filament material into short lengths (short fibers).
Either the short fibers are then cut to form a mat, or the short fibers are simply packaged as an intermediate product to serve as a supporting member.
In this way, the short fibers can be packaged as a prefabricated product in recess walls in automobile silencer casings or incorporated into sandwich-shaped panels for construction purposes. (Prior Art) Mechanically cutting glass filaments into short fibers requires a high-speed rotating machine. Short fibers are usually rough and have sharp edges, and have the property of abrading the skin, which can have an adverse physiological effect on the worker during the above-mentioned work. In the case of automobile silencer casings, the handling of short glass fibers is particularly problematic. As usual in automatic machine production lines for silencers, the air stream used to feed the glass fibers is generally It is difficult to quantify exactly how much fiber is released into the fiber. It is a well known method that continuous glass fiber rovings or slivers can be filled by passing them through a high velocity turbulent air stream before being deposited as fluff into the casing without cutting the filaments.
In EP-A-0091413, an automobile silencer casing is filled with bulky continuous filament glass fibers using a suction device which abuts the casing in order to obtain a deposit of the appropriate amount of glass fibers. It is proposed to use this known method for this purpose. The known method described above typically uses a fiber-filled or fiber-injection nozzle as the device for subjecting the continuous filament roving to a high-velocity turbulent air stream. Alternatively, a separate cutting device is used which is operable to cut the rovings when each muffler has been filled. SUMMARY OF THE INVENTION A common problem with known methods of filling silencer casings with glass fibers is ensuring that each filled material has a uniform packing density. Even with the provision of suction devices and/or auxiliary air evacuation devices, it becomes progressively more difficult for air to escape through the mass of fibers when the casing is filled to the brim with glass fiber material. Become. Also, because the material is bulky and elastic, it often bounces back toward the outlet of the filling nozzle device. This progressively reduces the quality of the filling operation. This results in the feed rate from the filling nozzle device slowing down as the outlet of the nozzle device becomes progressively blocked. This also means that the material that is last fed into the casing has a much lower packing density than the material that was initially fed, making it difficult to move the filled casing to the next production step, such as installing an end cap. This results in the value dropping to a point where it is even impossible to do so. This is because the filled material spills out from the ends of the casing. EP-A-0091413 discloses a method of filling a silencer casing, but only from one open end of the casing. Such filling methods are effective in approximately half of the commonly used types of absorbent silencers. However, there are other types very commonly used in absorption silencers, in which case the filling methods described above are ineffective and/or insufficient. For example, DC type (straight-
through) silencer, the automated production process of which involves attaching both end caps at once. In this case, it is usual to use a glass fiber blank which surrounds a length of the exhaust gas tube itself with a perforated wall, and to position said tube in the casing before fitting the end cap. This is the method of In this method, the step of creating intermediate products is an important and redundant step. There are also silencers that have absorbent regions filled with two separate glass fibers on either side of a reactive member that includes a baffle in the space that excludes the intermediate glass fibers. The absorbent regions may vary in shape and/or size, however it is common practice to fit both end caps together at once. SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved filling method and apparatus for filling a silencer casing with glass fibers. (Method for Solving Problems and Its Effects) The glass fiber filling method of filling the silencer casing with glass fibers according to the present invention is characterized in that both open ends of the silencer casing facing opposite to each other are filled almost simultaneously. The casing is characterized in that the casing is disposed facing toward two glass fiber filling parts, and the casing is filled with glass fibers from both the open ends of the casing. A lid is then applied to both said open ends, preferably simultaneously. Preferably, the method comprises feeding each of the glass fiber fillers with a continuous filament of glass fiber rovings and converting the rovings to a relatively lofty state before filling the casing with the glass fibers. including. Although the roving may be cut into short fibers before being filled, it is preferably supplied in the form of continuous filaments at the time of supply. Preferably, said roving is converted into said lofty state by air-streaming it with a well-known filling nozzle. More preferably, however, said airflow treatment is carried out by passing said roving through a filling nozzle having novel structural features as detailed hereinafter. The filling method according to the invention is preferably further characterized in that, prior to said filling, one end of a tubular spacing member is in each case temporarily placed against each said open end of said casing. Particularly in this case, it is advantageous to carry out the filling until there is an overflow of glass fibers in the spacing element, and in this case also to introduce the overflow glass fibers from the spacing element into the casing. A further pressing operation is added before the step of removing the spacing member and subsequently attaching the lid to both ends of the casing. The use of said spacing elements effectively increases the volume to be filled. Furthermore, even if there is overflowing material, it is not only completely contained within the spacing member, but also
By forcing the overflowing material into the casing from within the spacer, the casing can be filled to a substantially uniform density. Since it is relatively easy and accurate to measure glass fiber feed by length, the actual feed (mass) of filled glass fiber (short fiber or continuous filament) cannot be completely controlled. can. Only the filling amount and the pressure required to force the overflowing material into the casing need be monitored. When the filling is to be carried out around an unsupported through-walled tube, as is the case in a direct current silencer, the filling method according to the invention further comprises positioning and/or temporarily holding a tube with respect to the casing axially and radially until filled with sufficient material to support the tube; Probably. (Apparatus for Solving Problems and Its Effects) According to the second aspect of the present invention, the filling portion of the two glass fibers and the oppositely facing opening ends of the silencer casing are substantially connected to each other. At the same time, there is provided an apparatus for filling a silencer casing with glass fibers, characterized in that the apparatus includes a positioning apparatus for arranging the glass fibers toward the filling part. Preferably, each said filling section includes at least one filling nozzle, said filling nozzle being adapted to fill glass fiber rovings of continuous filaments before being placed therein as filled continuous filaments into said casing. has been made operational. Each filling section may have one or more filling nozzles and a separate roving feeding device for each such filling nozzle. The filling nozzle is made to reflect the cross-sectional shape and volume of the casing to be filled. According to another preferred feature of the invention, the filling nozzle comprises a roving introduction passage and an air flow introduction passage.
a distribution device for evenly distributing the air flow around the roving as a sheath-like member forming a generally annular space located in the area of contact between the roving and the air flow; a common exit passageway with the rovings, and in particular the restriction to the airflow due to the part of the annular space defined by the sheath located immediately in front of the contacting area, It is characterized in that the area of the exit passage is considerably less than that due to the area. It will be clear that the latter limitation is due to the exit passage during use, ie due to the flow of both airflow and glass fiber rovings. The effect of this is that the air flow passing through is no longer restricted by the air flow forming device formed within the sheath defining said annular space around the roving. Instead, the common exit passage has now become a very critical element. In the case of some filling operations in an automated process for filling automobile silencer casings with continuous filament glass fibers, for the inner diameter of said common outlet passage, preferably having a cylindrical and parallel-sided side wall. It has been found that the length ratio should be in the range 5 to 10, with a ratio of 8 being particularly preferred. At least the minimum amount required for fast filling of silencers on a production line basis.
At a typical roving feed rate of 500m/mm,
It has been found that the structure of the filling nozzle has a very important influence on the efficiency of the manufacturing process. That is, conventional fiber filling/injection nozzles were inadequate compared to the filling nozzle according to the present invention. This is because the air flow therethrough is limited in the invention only by the outlet passage and very large forces are applied to the roving in the outlet passage. This result not only provides excellent filling, but can also be used to eliminate the need for external mechanical cutting devices for the roving. It has been found that the force exerted on the roving in the outlet passage is virtually sufficient to break the roving if the roving supply is stopped. In order to eliminate the risk of the roving being blown out of the roving introduction channel in the opposite direction, after the roving has been cut in the filling nozzle, it is necessary to move the roving towards a holding device, e.g. It may be desirable to provide some type of roving fastening device that is operable. Prior art filling nozzles typically include an exit passageway having a ventilated throat and immediately following an outwardly diverging region in which the bulk of the charge is gradually reduced. It was meant to grow. In contrast,
The filling nozzle according to the invention not only preferably includes an outlet passage with parallel side walls, said passage is such that the air/roving mixture exiting therefrom undergoes a sharp, almost explosive expansion. Forms a sharp edge. Due to the unusually large forces generated on the roving in the exit passage, it is necessary to minimize leakage of air flowing back along the roving introduction passage. However, it is also highly desirable that the roving introduction passage not only accepts rovings, but also splices. because,
This is because it is advantageous to be able to splice the ends together between packages of rovings so that a nearly continuous operation can take place. The outer diameter of such a lap joint is
usually at least twice the outer diameter of the roving itself;
Therefore, the roving introducing passage has to be considerably larger than the roving only. These conflicting demands of low leakage and free passage of lap splices can be satisfied together by using a roving introduction channel with a length to internal diameter ratio of 10 to 20. Particularly when working with rovings having a linear density of 2000 to 5000 tex, a ratio of 16 is particularly preferred. One or more rovings can be used to obtain the desired roving density in the filling nozzle. Common to muffler casing filling operations using the filling nozzle according to the invention is that the risk of entanglement occurring within the (or each) roving fed to the filling nozzle is minimized. is necessary. This problem is further exacerbated by the fact that the filling operation of the silencer casing is a batch process, resulting in rapid stop-start operations.
In actual numbers, the supply of said roving is usually
From there (and up to) extremely high linear speeds of over 500 m/min, it must be stopped and restarted. This problem is solved by eliminating conventional tension control devices, thread take-up devices, etc. Instead, a godet wheel is used which is driven via a clutch/brake unit. The clutch/brake unit serves to provide a fully controlled speed for deceleration from and acceleration to the desired speed. This allows continuous operation equipment to be used and minimizes the mass of hardware to stop and start. An electrically or electronically controlled clutch/brake unit can be used to improve stop-start characteristics and to minimize changes in roving tension to the point where they are no longer a significant factor. It is particularly preferable to The filling nozzle according to the invention is particularly useful in the production of the glass fiber filled silencer casing itself, but also as a shaped glass fiber prefabricated product adapted for later insertion into the silencer casing. It will be understood that it can be similarly used in the process of making . Such intermediate products are processed and bonded with a very small amount of bonding material.
This is required for silencer casings which, due to their shape and/or internal complexity, cannot readily be subjected to an automated filling process. Further preferred embodiments of the structure of the filling nozzle will be explained later with reference to the accompanying drawings. Preferably, the filling device of the present invention includes a tubular spacing member arranged in association with each said filling portion, and a positioning member for arranging said spacing member oppositely at one open end of said casing, whereby said spacing is The member is adapted to form an extension of the casing intermediate the casing and the filler. More preferably, the filling device is configured to force overflowing glass fibers from the spacing member into the casing before moving the casing to a device operable to apply lids to the open ends of the casing. Contains an actuatable pressing device. Preferably, the volume of the spacing member is not critical, but rather should be up to about 50% of the volume of the muffler casing itself. Preferably, the spacing element has a cross-sectional shape similar to the silencer casing to be filled. Furthermore, it is preferred to have an elastic surface abutting the area to be used in order to prevent leakage from the casing. This is beneficial in minimizing both leakage and mechanical alignment problems. It will be appreciated that the actual cross-sectional shape of the spacing member and/or the muffler casing is not critical. The invention is equally equally adaptable to oval, oval or circular cross-sections encountered in the automotive industry. When there is an unsupported through-walled tube to be positioned within and relative to the casing, the filling device preferably ensures that at least the tube is connected to the glass fiber filled in the casing. It includes a positioning device for so supporting until it is sufficiently supported.
A magnet associated with each filler is a preferred positioning device for temporarily positioning the tube to be supported by and relative to the filler, so that air is directed below and through the filler. This allows them to escape without interfering with the filling operation. The two filling parts are mounted on a common support rail arrangement, and both filling parts abut, for example by means of air cylinders, oppositely facing open ends of the silencer casing towards each other. can be moved forward. The casings are arranged oppositely between the two filling sections under the influence of the form of a conveyor system. During the filling operation and before returning to its original starting position, each headstock itself
It may traverse the conveyor system. In the starting position the headstock engages with the next casing to be filled. Obviously the details of the equipment employed will reflect the nature of the silencer production line. However, the filling nozzle and spacing member/pressing device are preferably those described above. The invention further includes a silencer production line using the apparatus of the invention or a method modified to carry out the filling method of the invention. EXAMPLES In order that the invention may be better understood, examples of the invention will be described below with reference to the accompanying drawings. In FIG. 1, a cylindrical casing 1 includes a through-walled tube 2 centrally located and extending between and through the end caps 3 and 4. The space surrounding the tube 2 is filled with glass fibers 5. When not filled with glass fibers 5, the tube 2 has no support unless the lids 3, 4 are joined to the tube 2 and the casing 1. In Figure 2, a similar casing 1 and lid 3,
4 is used, each of the through-walled tubes 2 consists of two tube parts 6, 7, and each end of the tube parts 6, 7 overlaps inside the casing 1 and forms an internal partition 9, respectively. , 8. The partition walls 9, 8 and the casing 1 define a dead end space 10 between two separated spaces 11, 12 filled with glass fibers. 3 and 4, one open end 16 of a straight-through muffler casing has a length of through-walled tube 17 inside it. It is shown placed in the It is the filling section that is adapted to advance axially towards the open end 16. For simplicity, only a portion of the filling section is shown. The casing is supported by a conveyor (not shown).
The conveyor is provided with a magnet operable to hold the tube 17 against the casing until it is engaged by a filler. Said filling part includes a tube-shaped spacing element 13, said spacing element 13 having an elastic edge 14 positioned towards the open end 16 of the casing and shaped to seal it.
has. The central support member 15 is connected to the spacing member 13.
and the shaved end 18 of the central support member 15 engages the tube 17 and lifts it from the inner wall of the casing to the desired position relative to the centerline of the casing, as shown in FIG.
The center 19 of the support member 15 has a tube 1 with a through-hole wall.
It is hollow to allow air to escape from the casing through holes 7. It will be seen that the opposite ends of the casing are fitted with identical equipment, so that filling takes place from both ends at once. The length of the tube 17 will normally be longer than that of the casing, and in that case the length of the support member 15 will be suitably modified to accommodate the protruding portion of the tube 17 extending beyond the end of the casing. can do. A squeezing device, not shown for simplicity, is provided;
It is used to compact the glass fibers overflowing into the casing from the inside of the spacing member 13. After such compaction work, the tube 17
no longer normally requires support. The muffler casing tube and the material filled therein are then sent to the next step for attaching the end cap in the usual manner. Figures 5 and 6 show an alternative embodiment of the device in which a support plate 31 supports two filling outlets or filling nozzles 32,32. Each filling nozzle 3
2 is supplied with a continuous filament glass fiber roving 34 and high pressure air (usually 450 KN/M ² ) through a pipe 33. Each nozzle 32 is preferably of the type described below. The support plate 31 has an elastic surface 35 that abuts towards the open end of the muffler casing 36 . Casing 3
6 incorporates an exhaust gas tube 37 with a through-hole wall, and the free end of the tube 37 is connected to the support plate 31.
It abuts against and is positioned by a positioning bearing 38 provided protrudingly above. This also prevents glass fibers from being blown down and accumulating within the tube 37. Both ends A of the tube 37 are open to allow air to freely escape from the casing 36 during the filling operation. Each roving 34 is metered and fed from a roving package (not shown) by godet wheels (not shown) operated in the manner previously described. The operation of the filling section described above causes the glass fibers 40 to be rapidly filled into the casing to a packing density of at least close to about 50 Kg/m ³ , or to a typical purpose in the range of 80 to 100 Kg/m ³ . Up to about half the packing density can be obtained. The quality of the filling operation deteriorates from then on until the free passage of material into the casing becomes significantly reduced and as a result it stops. This creates an unstable transient state for the equipment/work, so
As a result, when moving on to the manufacturing process to attach the end cap to the next casing, this results in variations in packing density, combined with some material spilling out of the casing. 7 and 8 show a further improvement of the apparatus of FIGS. 5 and 6, in accordance with preferred features of the invention. In other words, the spacing element 50 has a resilient contact edge 51 that abuts against the muffler casing and is inserted between the casing 36 and the support plate 31 . An extension 58 matching the previous positioning bearing 38 projects to position the through-walled tube 37 and close it. a push plate 52 and a rod 53 operable to move the push plate 52 toward and into the inlet portion 54 of the casing as shown by the dashed line;
is provided. The push plate 52 is shaped to slide around the positioning bearing 38, and is provided with a cutout so as not to interfere with the filling nozzle 32. Other than the fact that the spacing member 50 space available for filling is now added for a given amount of glass fiber, the operation is otherwise exactly the same as before. By making the volume of this space approximately 50% of the volume of the muffler casing, the problems of the device/method described above are overcome. However, some filled material may spill into the spacing member 50 itself. The filling operation is completed by actuating the push plate 52 to conveniently move/compress this overflow material into the muffler casing, and the muffler casing is then processed for the next step to install the end cap. can be sent to. For the purpose of further illustrating particularly preferred features of the invention, a schematic side cross-sectional view (in enlarged scale) of another embodiment of a filling nozzle according to the invention is shown in FIG. Said filling nozzle has a main body 62 having an air flow introduction passage 65, a needle member 61 having a filament guiding member 64 opening into a roving introduction passage 67, and an outlet having an outlet passage 69 terminating in a raised flat surface 70. member 63. The needle member 61
is an annular space 66 defined inside the body 62
It ends with The open end of the needle member 61 located within the annular space 66 and the opposing inlet leading to the outlet passageway 69 cooperate to define an annular space 68 . i.e. annular space 6
8 extends between the annular space 66 and the inside of the outlet passage 69. In contrast to known filling nozzles, the effective area of said annular space 68 is reduced by relative axial movement of the needle member while maintaining a constant and acute contact angle between the air stream and the roving. There is no need for the needle member to be slidably mounted to change the needle member. As mentioned earlier, exit passage 6
9 shape is a critical element. (Effects of the Present Invention) During use, compressed air is supplied to the air flow introduction passage 65. A continuous filament glass fiber roving passes through the needle member 61 for approximately 600 m/min using a range of exit passageway internal diameter dimensions.
supplied at a rate of min. The quality of the filling operation actually carried out and the time required to cut the roving (when stopping the feed) were measured. The results were as follows.

[Table] Cutting is done at the exit passage 69 before exiting from the exit passage 69.
It was observed that the force was applied at a position approximately 6 mm deep inside the body, and it was confirmed that an intense force was clearly generated. Tests of the roving introduction passage 67 were conducted using both regular roving and spliced roving. Analysis of the above results confirmed that both the optimum (minimum) cutting time and the best filling quality are simultaneously achieved primarily as a function of the air inlet volume. Table 2 Text Rover introduction passage diameter Tex (mm) 2400 2.5-3.0 4800 3.0-4.0 With a preferred length to diameter ratio of 16, diameters in the above range give usable results. Note that the 4800 tex described above is formed by two separate 2400 tex rovings. This makes it possible for the filling nozzle according to the invention to use more than one roving with good results, thus providing a much greater throughput of material per unit time than filling nozzles of conventional products. have Using a filling nozzle of the type described above,
It will be clear that it is extremely useful for the purpose of the present invention, namely the filling of automobile silencer casings with glass fibers.

[Brief explanation of the drawing]

Figure 1 is a schematic side sectional view of a "DC type" silencer.
Figure 2 is a schematic side sectional view of a double-lid silencer with a free space without glass fibers in the center, and Figures 3 and 4 show the fabrication of the silencer shown in the schematic side sectional view in Figure 1. 3A and 3B are process step diagrams illustrating the operation of preferred embodiment apparatus components for carrying out the manufacturing method according to the present invention. Fig. 5 is a side sectional view showing the filling part shown in Fig. 4 in more detail, Fig. 6 is a front view of the filling part shown in Fig. 5 seen from direction A, and Fig. 7 is a modification of Fig. 5. FIG. 8 is a front view seen from direction A in FIG. 7, and FIG. 9 is an internal structure of a particularly preferred embodiment of the filling nozzle used in the filling section shown above. FIG. 1,36...Casing, 2,17,37...
Tube with transparent hole wall, 3, 4... Lid, 16... Open end, 5, 40... Glass fiber, 13,
50... Spacing member, 18... Shaved end (positioning device), 31... Support plate (positioning device), 32...
...Filling nozzle (filling part), 34...Roving, 38...
... Positioning bearing (positioning device), 52 ... Push plate (pressing device), 58 ... Extension part (positioning device), 62 ... Main body (sheath-shaped member), 65 ... Air introduction passage, 66, 68 ... Annular space, 67...
...Roving introduction passage, 69...Exit passage.

Claims (1)

[Scope of Claims] 1. Two oppositely facing open ends of a silencer casing are arranged facing each other toward two glass fiber fillings almost simultaneously, and from the two open ends of the casing, A method for filling a silencer casing with glass fibers, comprising filling the casing with glass fibers. 2. The method of claim 1, wherein each of the glass fiber filling stations is supplied with a continuous filament glass fiber roving, and before filling the casing with the glass fibers, the method comprises: A method of filling glass fibers comprising converting roving into a relatively bulky state. 3. In the method according to claim 1 or 2, the roving is fed after being cut into short fibers before being filled, or remains as a continuous filament during feeding. Glass fiber filling methods, including either supplied with or. 4. The method of claim 2, wherein the method comprises converting the roving into the bulky state by passing the roving through a filling nozzle; The nozzle directs the air flow around the roving as a sheath-like member forming a roving introduction passage, an air flow introduction passage and a generally annular space located in the area of contact between the roving and the air flow. a distribution device that evenly distributes the
a common exit passageway for the airflow and the rovings, and the restriction to the airflow is due to a portion of the annular space defined by the sheath located immediately in front of the contact area; , due to the area of the common exit passage, which is considerably less than that of the glass fiber filling method. 5. In the method according to any one of claims 1 to 4, the method includes the step of: attaching one end of the tubular spacing member in contact with the both opening short portions of the casing before the filling. 1. A method of filling glass fibers comprising temporarily positioning portions of the fibers. 6. The method of claim 5, further comprising removing the glass fibers from within the spacing member before removing the spacing member to attach lids to the openings of the casing. A glass fiber filling method involving extrusion into a casing. 7. In the method according to any one of claims 1 to 6, when the through-walled tube is placed in the casing without any support, the glass fiber filling method , positioning and/or temporarily supporting the tube relative to the casing until it is filled with at least enough of the glass fibers such that the tube is axially and radially supported relative to the casing; Glass fiber filling method including. 8. A silencer casing characterized in that it includes a filling portion of two glass fibers and a positioning device for arranging both mutually opposite open ends of the silencer casing toward the filling portion substantially simultaneously. Glass fiber filling equipment. 9. Apparatus according to claim 8, wherein each said filling part comprises at least one filling nozzle, which before being placed into said casing as a continuous filament filled therewith: A glass fiber filling device operable to fill continuous filament glass fiber rovings. 10. The device according to claim 9, wherein the filling nozzle has a roving introduction passage, an air flow introduction passage and a generally annular space located in the area of contact between the roving and the air flow. a distribution device for evenly distributing the air flow around the roving as a forming sheath, and a common exit passageway for the air flow and the roving; wherein the restriction to the airflow due to the portion of the annular space defined by the annular space located immediately in front of the contact area is significantly less than that due to the area of the common exit passage. . 11. The device according to claim 10, wherein the outlet passage of the filling nozzle is parallel-sided and cylindrical, and has an inner diameter of 5 to 10 The roving introduction passage has a length in the ratio of 10 to 20 to the inner diameter. 12. The device according to claim 8, wherein each of the filling portions includes an associated tubular spacing member and an arrangement device for arranging the spacing member oppositely at one open end of the casing. , wherein the spacing member forms an extension of the casing that is intermediate between the casing and the filling section. 13. The apparatus of claim 12, wherein the apparatus is configured to remove overflowing glass fibers before moving the casing to a device operable to apply lids to the open ends of the casing. a pushing device operable to force the fibers from the spacing member into the casing. 14. In the device according to any one of claims 8 to 13, when the casing has a tube that is not supported in any way, at least the tube is filled with the casing. A glass fiber filling apparatus including a positioning device for positioning the unsupported tube within and relative to the casing until it is fully supported by the glass fiber. 15. The apparatus of claim 14, wherein the positioning device includes a magnet.