Hose connecting structure

Abstract: The present invention relates to a hose connecting structure comprising a hose (10) in which at least the central portion (16) comprises a thermal flexibility resin which is molded by a blow molding method; a mating member (28) which is inserted into the edge opening of said hose, or into which the edge portion of said hose is inserted; a ring-shaped sealing material (14); a first engaging portion (22) which is disposed in the axial direction with a predetermined distance to said sealing material at an edge portion of one of said hose and said mating member; and a second engaging portion (36) which is directly or indirectly engaged with said first engaging portion at the other of the edge portion of said hose and said mating member, wherein said engaging portion of said hose is integrally formed with said hose by the blow molding method and located on the same side wall of said one of said hose and said mating member on which side wall said sealing material rests, wherein the portion of the other said hose and said mating member cooperating with said sealing material is free of a specific adaption.

Description: The present invention relates to a hose connecting structure which is suitable for use as a connecting structure when an air duct hose or a filler hose is connected with a mating member. Concerning an air hose or a filler hose for an automobile, it is recently examined and actually practiced that a resin hose is used instead of a rubber hose. When the resin hose is used as the air hose for the automobile, a negative pressure is applied on the air hose. So, it is better that the resin hose is made of a hard resin material in order to obtain the negative pressure resistance. Conventionally, the air hose is incorporated into the automobile in the following manner. A mating pipe is inserted into a hose edge opening to connect the hose edge portion and the mating pipe. At that time, a clamp member clamps the hose edge portion and the mating pipe from an outer surface of the hose. This clamping prevents the hose edge portion from falling out. The hose edge portion is adhered to the mating pipe elastically so that the sealing capacity is ensured. Therefore, in this conventional connecting structure, it is needed that the hose edge portion is closely adhered to the mating pipe. Although, when the hose is made of a hard resin material, the hose edge portion cannot be fully adhered to the mating pipe. Thus, concerning an air hose made of resin, it is considered that the body portion of the hose is made of a hard resin material, and the edge portion of the hose is made of a soft resin material. This is true of a filler hose or other hoses. For example, in the filler hose, it is considered that the body portion of the hose is made of a hard resin material in order to obtain the oil resistance. It is further considered that the edge portion of the hose is made of a soft resin material. Since the above resin hose requires the curved portion and the bellows portion, a blow molding method is preferably used to form the hose. In the blow molding method, a tubular or a bladder-like parison is swelled by blowing an air so that the parison is closely adhered to an inner surface of the mold. As a result, the parison is formed in the predetermined shape. Thus, the outer surface of the molded hose is accurately formed in the predetermined shape by the mold, but the inner surface of the molded hose is formed under the free condition. Therefore, the inner surface of the molded hose shows bad characteristics in its shape and dimensional accuracy. Concerning an air hose, a mating member such as a metal pipe is inserted into a hose edge opening, and a clamp member clamps the mating pipe and a hose edge portion. As a result, the hose edge portion is closely adhered to the mating member so that the sealing capacity is ensured. Therefore, when the hose shows bad characteristics in its shape of the inner surface of the hose edge opening and the dimensional accuracy, i.e. the inner diameter and the thickness shows unevenness, the sealing capacity cannot be achieved satisfactorily. Concerning the resin hose formed by the blow molding method, the inner surface of the edge portion is polished so that the hose is formed in the predetermined shape and dimension. When the polishing is performed, a hose forming step becomes complicated, and polishing powders remain at and around the polished portion. Therefore, a washing step is needed, and the hose forming step becomes more complicated. As a result, a forming cost is increased. The above are problems about the resin hose formed by the blow molding method. When the hose edge portion is made of a soft resin material, the following problems arise. There are few kinds of soft resin materials for ensuring the excellent sealing capacity. The selection of the soft resin materials is restricted for satisfying other characteristics of the hose. The filler hose requires the oil resistance and so on. Recently, regulation of oil penetration resistance becomes severe, but the soft resin material cannot meet such demand. The air hose loaded on a turbo engine car requires heat resistance. In this case, the soft resin material cannot meet such demand. The air hose or the filler hose for automobiles determines its shape with respect to its attachment space and the mating member. When the above hoses are formed, the body portion of the hose is formed in the predetermined shape at the molding stage. Furthermore, each edge portion is performed to connect the mating member. The length and the shape of the hose is different according to the type of the car, the shape and the kind of the mating member, or the attachment space. In this case, each hose must be formed in each different mold according to each different length and shape. When the above hoses require each different mold, the amount fee for molds is expensive. Especially, when a few variety hoses are formed, the forming cost is high. A hose connecting structure is known from the EP-A-0 002 197, according to which blow-molded hoses are connectable with mating members. Furthermore, a hose connecting structure of a blow-molded hose is known from the GB-A-1 036 459 which shows that a ring-shaped sealing member is simultaneously used as an engaging portion. Also EP-A-0 223 495 shows a prior art hose connecting structure with blow-molded hoses. Peripheral beads, which are part of the hose at its free end, interfere with a second engaging portion of a mating member, when the hose is inserted into the mating member. According to EP-A-0 435 360, the sealing of a hose connecting structure is provided by the engagement between the hose and the mating member. The hose connecting structure of EP-A-0 385 465 is such that no engagement portions are provided, but instead the engagement is performed by a sealing member. US-A-3 838 713 shows that the engagement and the sealing of the hose connecting structure is simultaneously performed by one and the same portion. It is an object of the present invention to provide an improved hose connecting structure. This object is achieved by the features of claim 1. Advantageous further developments are set out in the dependent claims. At least the intermediate portion and the engaging element of the hose connecting structure according to the present invention comprises a thermal flexibility resin which is molded by a blow molding method. The mating member comprises resin, metal and other structure materials. The end portion of the hose can be inserted into the opening of the mating member. The hose has a ring-shaped sealing member. Usually, the O-ring is used as the sealing member. When the engaging clearance is largely varied, other sealing members such as the cross sectional V-shaped, Y-shaped, W-shaped and X-shaped sealing member can be used. The hose has a sealing groove and the sealing member is hold to the sealing groove. The sealing groove is a ring-shaped groove which encircles the engaging surface of the end portion of the hose in the circumferential direction. The hose can have one sealing member or more than two sealing members. The sealing member can be hold to the mating member. The hose has a first engaging element which is disposed in the axial direction with the predetermined distance to the sealing member. The first engaging element can be disposed either at the end surface side or at the intermediate side from the viewpoint of the sealing member. The second engaging element is disposed at the mating member. The first engaging element and the second engaging element have the relationship that one can be engaged with or released from the other and vice versa. The structure of these engaging elements can be conventional. For example, the second engaging element can be a lock ring, an engaging claw or one of the pair of engaging structures which is formed by the projection and the recess. When the second engaging element is formed as the lock ring, it is preferable that a part of the ring-shaped groove has a wide length so as to enlarge or decrease the diameter of the lock ring for the purpose of releasing the engage of the lock ring. The lock ring is disposed at the opening end portion of the mating member, and a tapered guide surface whose inner periphery diameter is increased is disposed at an opening side at which an opening is elastically deformed in the shaft center direction. The engaging claw can be an engaging arm comprising an arm portion which projects from the outer periphery surface in the radial direction toward the end side, and an engaging claw which is disposed at the end of the arm portion. A plural of the engaging arms are preferably disposed at the outer periphery surface of the hose in the circumferential direction. These engaging arms are molded by the injection molding method. In this method, the body portion of the hose which has the edge portion and which is molded by the molding method is inserted. The engaging arm which is formed by the injection molding is inserted to be formed integrally. As above described, the hose comprises the resin material which is molded by the blow molding method. The end portion is inserted in the inner surface of the mating member by way of the sealing member such as an O-ring. In the present invention, the end portion of the hose molded by the blow molding method is engaged with the inside of the mating member. In other words, the outer surface of the end portion of the hose in which the dimensional accuracy is excellent is used as the engaging surface of the connecting portion. Furthermore, the sealing of the connecting portion is achieved by the sealing member such as O-ring, not by the elastic adhesion of the edge portion of the hose to the mating member. As a result, after the blow molding of the end portion of the hose, the step of polishing the inner surface of the end portion and the step of washing the polishing powder are omitted. Therefore, the step of forming the hose is simplified. Since the polishing step is omitted, disadvantages caused by the remain of the polishing powder can be solved. In the present invention, when the hose is made of the resin material, the end portion of the hose can be made of the soft resin material or the hard resin material. As a result, the selection of the soft resin materials is restricted for satisfying other characteristics of the hose. In the conventional way, a connection metal fitting is fixed to the end portion of the hose by the calking method for the connection of the hose. Generally, the connection metal fitting is fixed to the mating member. In the above case, it is required that the metal fitting having a complicated structure is fixed to the end portion of the hose. Therefore, many components are required, and the hose connecting structure becomes complicated. Furthermore, the cost is high. In the present invention, the engaging portion for the connection and the end portion of the hose are integrally formed. Therefore, the conventional metal fitting is not required, and many components are not required. Furthermore, the cost is low. Moreover, the end portion made of the resin material is engaged with the mating member. In other words, the end portion is used as a part of the connection coupling, so the connecting structure is simplified. In the present invention, the engaging element is disposed at each of the end portion of the hose and the mating member. Since one engaging element is engaged with the other engaging element in the axial direction by way of the lock ring which is deformable, the hose cannot be drawn out. The first engaging element is disposed at the end side from the sealing groove of the sealing member, and the second engaging element is disposed at the corresponding portion. In this case, when the end portion of the hose is inserted into the mating member, the sealing member doesn't pass through the second engaging element. Therefore, the sealing member is not damaged by the connection or contacting between the sealing member and the second engaging element. The first engaging element is disposed at the side to which the sealing member is hold, so the first engaging element is not contacted to the sealing member. Since the sealing member is not contacted to the second engaging element, the second engaging element can be disposed near the sealing member in the direction which is perpendicular to the axis. Therefore, the second engaging element cannot be projected toward the outside or the inside in the direction which is perpendicular to the axis. When the hose is molded by the blow molding method, the step such as the polishing of the end portion is not required for increasing the dimension. Therefore, the step of washing the polishing powder can be omitted, and the step of forming the hose is simplified. Since the polishing can be omitted, disadvantages caused by the remain of the polishing powder is solved. Furthermore, the end portion is made of the hard resin material, so the cost for the material is lowered. Figures 1 (A) to (C) show the hose connecting structure of a comparative example. Figure 1 (A) is a main plan view, partly in cross section, before connecting. Figure 1 (B) is a main plan view, partly in cross section, after connecting. Figure 1 (C) is a perspective view for showing the end portion of the resin hose. Figure 2 is a plan view for showing the whole structure of the resin hose described in Figure 1. Figures 3 (A) and (B) are explanatory drawings for showing the method for forming the end portion of the resin hose described in Figure 1 (C). Figure 3 (A) is a main cross sectional view for showing the mold when the body portion of the hose is inserted. Figure 3 (B) is a main cross sectional view when the mold is opened. Figures 4 (A) and (B) are explanatory drawings for showing the process of the other method for forming the resin hose of the comparative example. Figure 4 (A) is a main cross sectional view before clamping the mold. Figure 4 (B) is a main cross sectional view when the compress gas is introduced. Figures 5 (A) and (B) are explanatory drawings for showing the process of the method for forming the variation of the resin hose of the comparative example. Figure 5 (A) is a main cross sectional view before clamping the mold. Figure 5 (B) is a main cross sectional view when the compress gas is inserted. Figures 6 (A) to (F) are drawings for showing a hose connecting structure of an embodiment according to the invention. Figure 9 (A) is a main cross sectional view when the other resin hose and the other mating member are used. Figure 6 (B) is a main cross sectional view when the other mating member is used. Figure 6 (C) is a main cross sectional view when a further mating member is used. Figure 6 (D) is a main cross sectional view when a further mating member is used. Figure 6 (E) is a main cross sectional view when a further mating member is used. Figure 6 (F) is a main cross sectional view when a further mating member is used. Figures 7 (A) and (B) are drawings for showing the other resin hose which is used for the hose connecting structure of the embodiment. Figure 7 (A) is a cross sectional view. Figure 7 (B) is a plan view. Having generally described the present invention, a further understanding can be obtained by reference to the specific preferred embodiments which are provided herein for purposes of illustration only and are not intended to limit the scope of the appended claims. The preferred embodiment according to the present invention will be hereinafter described with reference to Figure 6. Comparative Example Figure 2 is the plan view showing whole of the hose 10. This hose 10 comprises body portion of the hose, which is made by a blow molding method and which has a predetermined curved shape, and a plurality of the first engaging portions 16 which are integrally fixed to the body portion of the hose. The intermediate portion of the hose 10 has a bellows portion which comprises a soft resin material. The rest of the portion comprises a hard resin material. Each of the first engaging portions 16 comprises: a base 18 which is integrally welded and fixed on the outer peripheral portion of the body portion of the hose; a pair of rising portions 19 and 19 which rise up from the both ends of this base 18; a pair of elastic arms 20 and 20 which are parallelly extended from the upper edge of the rising portions 19; and an engaging claw 22 which is disposed for connecting the tips of elastic arms 20 and 20. A plurality of these first engaging portion 16 form the ring which makes a round by being connected by ring connecting portions 24 with one another in the circumferential direction. The base 18 and the connecting portion 24 are incorporated into the inner side of a ring groove 26 which is formed on the hose 10 and it is integrated by welding with the groove 26. So, the surface of the connecting portion 24 is on a level with the outer surface of the hose 10. The cross-sectional structure of the hose 10 can be a single layer structure or a lamination structure. As shown in Figure 1, two O-ring grooves 12 and 12 are formed on a tip portion periphery surface 11 of the hose 10, and two O-rings 14 and 14 are attached to the O-ring grooves 12 and 12 respectively for sealing the hose 10. When the O-ring 14 is used for a filler hose, it is better to comprise the materials such as NBR or FKM. The O-ring 14 can comprise other materials. A pipe-shaped mating member 28 comprises a metal material for connecting with the hose 10. The mating member 28 has a large-diameter portion 30 at the edge side, and the inner surface of the large-diameter portion 30 is an engaging surface 32. The large-diameter portion 30 is tapered at the bottom portion, and this tapered portion is a stopper portion 34. The stopper portion 34 contacts with the hose 10 to control an excess push. The large-diameter portion 30 is curved and returned at the edge portion, and this curved return portion is a second engaging portion 36 for engaging with the first engaging portion 16. In the hose connecting structure, when the end portion of the hose 10 is inserted into the inner portion of the mating member 28, the first engaging portion 16 comes to be elastically engaged with the second engaging member 36 to prevent the hose 10 from falling out. The stopper portion 34 connects with the edge portion of the hose 10 to control an excess push. Figure 1(B) shows the enlarged cross-sectional view showing the major portion in the connecting state of the hose and the mating member. The excess push can be controlled by contacting the edge portion of the mating member 28 and the rising portion 19 of the first engaging portion 16. When the end portion of the hose 10 is inserted into the inner portion of the mating member 28, the outer surface 11 of the end portion is engaged with the inner surface 32 of the mating member 28 through the O-ring 14 which is used for obtaining the seal at the engaging portion. Since the body portion of the hose 10 is made by blow molding method, the outer surface 11 has a high dimensional accuracy. In the present invention, it is advantageously possible to use the outer surface 11 as the engaging surface when the hose 10 is inserted into the inner portion of the mating member 28. Figure 3 shows the method for producing the hose 10, concretely, the method for producing the first engaging portion 16. In Figure 3, 38 is a core die, and 40 is the body die. The body die 40 comprises two split dies 42 and 44 to form a molding cavity 46. In this method, as shown in Figure 3(A), a resin material is injected into the molding cavity 46 under the condition that the body portion of the hose 10a is set in the molding die. The resin material is solidified to integrally form the first engaging portion 16 and the hose 10. The base 18 and the connecting portion 24 of the first engaging portion 16 are deposited to the inner surface of the groove 26 of the body portion of the hose 10a by means of the heat caused by the injection molding. As the result, the base portion 18 and the connecting portion 24 are stably fixed to the groove 26. If the deposition is not enough, the base portion 18 and the connecting portion 24 are physically engaged with the inner surface of the groove 26, so that they are firmly fixed to the groove 26. After the first engaging portion 16 is molded, as shown in Figure 3(B), the split dies 42 and 44 are separated in the direction of the hose axis to obtain the products. The split die 44 is rotated at the predetermined angle around the hose. Then after the molding portion 48 of the engaging claw 22 in the first engaging portion 16 is positioned between the engaging portions 16 and 16, the split die 44 is shifted in the direction of axis so as to go through the space between the first engaging portions 16 and 16. As the result, the split die 44 can be pulled out from the hose 10. In this comparative example, the split dies 42 and 44 are shifted to the direction of the hose axis and are separated so as to pull out the hose. By means of providing two or four engaging claws 22 of the first engaging portions 16, the split die 42 and 44 can be separated by shifting them in the direction which is perpendicular to the axis. The connecting portion 24 is fully incorporated into the inner side of the groove 26 of the hose 10, so this connecting portion 24 doesn't prevent the split die 44 from extracting. In the above-mentioned comparative example, the body portion of the hose 10a is molded at first and it is set in the injection molding die. And in this state, the first engaging portion 16 is injection molded. Figures 4(A) and 4(B) shows another method of molding. As shown in Figures 4(A) and 4(B), the first engaging portion 16 is injection molded in advance and it is set in a blow molding die, then the body portion of the hose 10a may be blow molded. In this case, the base and the connecting portion 24 of the first engaging portion 16 can be formed so as to enter into the inside of the body portion of the hose 10a. O-ring groove can also be molded at the body portion 10a at the same time of the blow molding by providing the projection 54 at the insert die (support die) in the blow molding die 52. Furthermore as shown in Figures 5 (A) and 5(B), the projection 54 is provided at the body die of the blow molding and the 0-ring groove can be molded by this projection 54. The above mentioned comparative examples are modifications in which the engaging claw is provided at the side of the first engaging portion. According to the invention, it is possible to provide the engaging claw at the side of the second engaging portion. Figure 6 shows an embodiment according to the invention. Figure 6(A) shows the modification in which the second engaging portion 146, having an elastic arm 148 and an engaging claw 150, is integrally molded with the mating member 28. Figure 6(B) shows the modification in which the separate member is integrated with the body portion 156 of the mating member 28 and the second engaging portion 162 having an elastic arm 158 and an engaging claw 160 is provided. Furthermore, Figure 9(C) shows the modification in which the C-shaped tube retainer 166 is attached to the side of the mating member 28 and an elastic claw 168, which is formed by cutting up the part of the claw member 166, engages with the flange shaped first engaging portion 152 at the side of the hose 10. Figure 9(D) shows the modification in which a groove 170 is provided at the side of the mating member 28; an elastic lock ring 172, whose diameter can be enlarged and reduced, is installed to the groove; and the elastic lock ring 172 is engaged with the first engaging portion 152 at the side of the hose 10. Figure 9(E) shows the modification in which the second engaging portion 182, having an elastic arm 178 and an engaging claw 180, is provided at the side of the non-pipe shaped mating member 28 with an opening 174 and this second engaging portion is engaged with the first engaging portion 152 at the side of the hose 10. Figure 9(F) shows the modification in which an elastic claw member 184 is installed to the side of non-pipe shaped mating member 28 and this elastic claw member is engaged with the first engaging portion at the side of the hose 10. The above-mentioned embodiments shown in Figure 6 have the following advantages. Not only the body portion of the hose and the edge portion for connecting can be molded by going through only one process i.e. the blow molding but also the first engaging portion can be molded at the same time. Accordingly the production process can be simplified so that the cost of it can be reduced. Also the structure of the second engaging portions can be formed in the shape and structure which correspond to the types of the mating member 28. One of the preferred embodiments of this invention has been detailed so far, but this invention is not limited thereto and may be realized in other forms. For instance, as shown in Figures 7(A) and 7(B), the hose may be a blow hose 15 in which the whole of the body portion of the hose may be bellows portion 13. And this invention is applicable to this blow hose and other various forms of hoses.

Claims: A hose connecting structure, comprising: a tubular hose (10a) having, at one end thereof, an end portion formed integrally with an intermediate portion in blow-molding the intermediate portion by a thermoplastic resin material, at least the end portion being formed by a hard thermoplastic resin material; a ring-shaped sealing groove formed on an outer peripheral surface of the end portion of said tubular hose (10a) in blow-molding the intermediate portion thereof; a mating member (28) including an opening end portion having an inner peripheral surface engageable with the outer peripheral surface of the end portion of said tubular hose (10a); a separate ring-shaped seal member attached to said ring-shaped sealing groove for sealing between the end portion of said tubular hose (10a) and the opening end portion of said mating member (28), when the opening end portion of said mating member (28) is inserted onto the end portion of said tubular hose; a first engaging element (152) formed on the outer peripheral surface of the end portion of said tubular hose (10a) integral with the end portion at a position more spaced than said ring-shaped sealing groove from an end surface of the end portion, said first engaging element (152) having a flange-shape and protruding radially outwardly from the outer peripheral surface of the end portion; and a second engaging element (146; 162; 166; 172; 182) provided adjacent to a tip portion of said opening end portion, the tip portion having an engagement inner diameter adapted to receive said first engagement element (152) for securing said tubular hose (10a) and said mating member (28), said second engaging element (146; 162; 166; 172; 182) deforming in a radial direction to engage with a blocking surface of said first engaging element (152) faced to another end of said tubular hose (10a), when the opening end portion of said mating member (28) is inserted onto the end portion of said tubular hose (10a). A hose connecting structure according to claim 1, characterized in that said second engaging element (146; 162) is comprised of a deformable arm (148; 158) provided at a tip portion of the opening end portion and extending axially outwardly, and an engaging pawl (150; 160) provided at a free end of the deformable arm (148; 158) and extending radially inwardly. A hose connecting structure according to claim 1, characterized in that said second engaging element (166) is a C-shaped retainer (166) held within a ring-shaped groove formed on the inner peripheral surface of a tip portion of the opening end portion. A hose connecting structure according to claim 3, characterized in that said retainer (166) is comprised of a C-shaped tube having an engaging pawl (168) at one end thereof. A hose connecting structure according to claim 3, characterized in that said retainer is comprised of a C-shaped resilient locking ring (172) made of a spring. A hose connecting structure according to claim 1, characterized in that the intermediate portion of said hose is formed by a soft thermoplastic resin material. A hose connecting structure according to claim 1, characterized in that said mating member is comprised of a pipe (28). A hose connecting structure according to claim 1, characterized in that said mating member is comprised of a receptacle. A hose connecting structure according to claim 1, characterized in that the intermediate portion of said hose (10a) has a bellow portion. A hose connecting structure according to claim 1, characterized in that the intermediate portion of said hose (10a) has a bellow portion formed by a soft thermoplastic resin material whereas the end portion and the rest of the intermediate portion of said hose (10a) is formed by a hard thermoplastic resin material.

Inventors: ICHIKAWA HIROYUKI, KAWASAKI MINORU, MIYAJIMA ATSUO, ICHIKAWA, HIROYUKI, KAWASAKI, MINORU, MIYAJIMA, ATSUO, Ichikawa, Hiroyuki, c/o Tokai Rubber Ind. Ltd., Kawasaki, Minoru, c/o Tokai Rubber Ind. Ltd., Miyajima, Atsuo, c/o Tokai Rubber Ind. Ltd.
Applicants: TOKAI RUBBER IND LTD, TOKAI RUBBER INDUSTRIES, LTD.
Application year: 1993
Main classification: F16L37
IPC codes: F16L11, F16L37