JP6822042B2 - How to make a rack and pinion housing - Google Patents

Description

The present invention relates to a rack and pinion housing, a rack and pinion type steering device, and a method for manufacturing the rack and pinion housing.

In recent years, there has been a strong demand for the promotion of fuel efficiency reduction for resource saving and energy saving of automobiles and CO ₂ reduction. There is a strong demand for weight reduction of electric power steering devices, and technological improvements are required every day. Conventionally, the housing for accommodating the rack and pinion of the EPS (Electric Power Steering) reducer (see the rack and pinion housing 100 in FIG. 1 described later) is generally made of a metal material, and in many cases aluminum is used. Was there. Currently, the trend is research and development on the replacement of metal materials with resin materials with a lower specific gravity. When the weight of the housing for accommodating the rack and pinion is reduced with a resin material, in addition to rigidity, dimensional stability, impact resistance, and deterioration of creep become problems. Therefore, the mechanical properties that deteriorate due to the change to the resin material have been reinforced by combining various fiber materials, and both high strength and light weight have been achieved.

As a prior art for combining such fiber materials, there is a technique for adhering a sheet-shaped prepreg (intermediate material) composed of carbon fiber and resin described in Patent Documents 1 and 2. Patent Document 1 discloses a rack housing formed by so-called sheet winding, in which a sheet-shaped intermediate material is wound around a tubular core rod and cured. In Patent Document 2, two laminated sheets in which a carbon fiber sheet and a thermoplastic resin film are laminated are set in a mold in a heated state, and the mold is molded to form a film on the carbon fiber sheet. A rack housing impregnated with a thermoplastic resin and pressed is disclosed.

Japanese Unexamined Patent Publication No. 2013-103652 Japanese Unexamined Patent Publication No. 2016-13673

However, in the above-mentioned conventional technique, it is difficult to form a complicated shape, and the characteristics of the sheet-like intermediate material affect the final product, and the strength between the layers of the sheet may become a problem. The reason is that there is no fiber material on the adhesive surface, and in addition, voids are generated due to poor curing of the adhesive (thermoplastic resin), resulting in insufficient adhesive strength. In particular, the parts that make up an automobile must be designed with sufficient strength to include a safety factor compared to general structural members, and it is possible to further ensure the protection of the rack and pinion of the EPS reduction gear. It is requested.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a rack and pinion housing in which high strength can be obtained while reducing the weight even if the shape is complicated.

The present invention has the following configuration.
A fiber material selected from at least one of glass fiber, carbon fiber, aramid fiber, aromatic polyamide fiber, liquid crystal polyester fiber, silicon carbide fiber, and boron fiber is opened in a solvent to obtain a fiber-containing slurry. A fibering process, a manufacturing process in which the fiber-containing slurry is injected into a manufacturing mold, and the solvent is removed from the manufacturing mold to form a preform having substantially the same shape as the finished product from the manufacturing mold, and the preform. The assembly step of assembling the connecting member to the boss portion formed in the above, and the preform to which the connecting member is assembled are loaded into the molding mold, and the preform and the connecting member are integrally molded with resin. A method of manufacturing a rack and pinion housing, comprising:

According to the present invention, a rack and pinion housing having high strength can be obtained while reducing the weight even if the shape is complicated.

It is the whole perspective view of the rack and pinion type steering apparatus. It is a perspective view of the rack and pinion housing shown in FIG. It is an enlarged perspective view of the 1st housing part shown in FIG. It is an enlarged perspective view which shows the other structural example of the 1st housing part. (A) to (F) are process diagrams for explaining the manufacturing process of the rack and pinion housing. (A) is a cross-sectional view showing the joint portion between the boss portion and the connecting member in which the connecting member is assembled to the boss portion, and (B) shows the joint portion between the boss portion and the connecting member after molding. It is a sectional view. It is sectional drawing as a reference example which showed the joint part which the housing containing the fiber material was joined to the connecting member by an adhesive. (A) is a cross-sectional view showing the joint portion between the boss portion and the connecting member in which the connecting member is assembled to the boss portion coated with the adhesive, and (B) is the cross-sectional view of the boss portion after molding and the connecting member. It is sectional drawing which showed the joint part.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an overall perspective view of a rack and pinion type steering device.
The column-assisted rack and pinion type steering device 10 includes a steering wheel 11, a column 13, an intermediate shaft 15, a motor 17, a steering gear unit 19, and a tie rod 21. The steering gear unit 19 includes a rack shaft 23, a pinion shaft 25, and a rack and pinion housing 100. The rack and pinion housing 100 has a housing portion 27 that covers the outside of the rack and pinion, and a plurality of joint portions 29 that are formed in a part of the housing portion 27 and to which members to be joined are connected. Each joint 29 has a boss, which will be described later, and a metal connecting member.

The rack shaft 23 has rack teeth on at least a part of the outer circumference, and is supported by the housing portion 27 so as to be reciprocally driven in the axial direction. The pinion shaft 25 has a pinion (not shown) that is attached to the lower end of the steering shaft including the intermediate shaft 15 and meshes with the rack teeth of the rack shaft 23.

The rack and pinion type steering device 10 applies a steering assist force that reduces the operating force of the steering wheel 11 to the steering shaft from the motor 17 attached to the intermediate portion of the column 13. Then, the rotation of the steering shaft is transmitted to the rack shaft 23 via the pinion shaft 25, so that the rack shaft 23 is reciprocated.

Tie rods 21 are connected to the left and right ends of the rack shaft 23, and each tie rod 21 is connected to a wheel (not shown). Therefore, in the rack and pinion type steering device 10, when the driver rotates the steering wheel 11, the pinion shaft 25 attached to the end of the steering shaft rotates the pinion housed in the housing portion 27. As a result, the rack shaft 23 supported by the housing portion 27 is reciprocated to the left and right, and the wheels are steered via the tie rod 21.

FIG. 2 is a perspective view of the rack and pinion housing shown in FIG. 1, and FIG. 3 is an enlarged perspective view of the first housing portion 28 shown in FIG.
As shown in FIGS. 2 and 3, the housing portion 27 of the rack and pinion housing 100 is a hollow cylindrical portion 31 that covers the rack shaft 23 (see FIG. 1) and a pinion housing on one end side in the axial direction of the hollow cylindrical portion 31. It has a first housing portion 28 and a second housing portion 32 on the other end side in the axial direction. The first housing portion 28 and the second housing portion 32 are provided with joint portions 29 to which connecting members are attached to the boss portions at a plurality of locations.

Specifically, the first housing portion 28 includes a boss portion 33 for inserting a pinion, a boss portion 35 to which an adjustment spring (not shown) is fixed, and a boss for fixing the vehicle body to be attached to a vehicle body frame (not shown) such as a front subframe. It has a portion 37 and a boss portion 45 to which one tie rod is connected. The second housing portion 32 has a boss portion 47 to which the other tie rod is connected, and a boss portion 39 for fixing the vehicle body.

A connecting member 49 having a female screw formed on the inner peripheral surface is attached to the boss portion 33. A connecting member 51 having a female screw formed therein is attached to the boss portion 35. Sleeve-shaped connecting members 53 and 55 are attached to the boss portions 37 and 39 for fixing the vehicle body. Further, connecting members 57 and 59 are attached to the boss portions 45 and 47. Each connecting member 49, 51, 53, 55, 57, 59 is made of an iron-based material, a non-ferrous metal-based material, or a hard resin material.

A pinion shaft 25 (see FIG. 1) is inserted into the boss portion 33, and the pinion at the lower end of the inserted pinion shaft 25 meshes with the rack teeth formed on the rack shaft 23. Further, bolts (not shown) are inserted into the holes of the connecting members 53 and 55 in the boss portions 37 and 39 for fixing the vehicle body, and by fastening these bolts to the vehicle body frame, the rack and pinion housing 100 can be attached to the vehicle body frame. Is fixed to.

By attaching connecting members 49, 51, 57, 59 to each joint 29, the joint strength with the members to be joined such as bolts and tie rods can be increased.

The first housing portion 28 may have a configuration shown in FIG. 4, for example, in addition to the configuration shown in FIG.
FIG. 4 is an enlarged perspective view showing another configuration example of the first housing portion.
In the first housing portion 28A shown in the figure, a connecting member 49A arranged on the boss portion 33 for inserting a pinion is arranged so that one end thereof is exposed. Further, the connecting member 57A arranged on the boss portion 45 is also arranged with one end thereof exposed.

Since the ends of the connecting members 49A, 57A, etc. are exposed to the outside of the housing as in the first housing portion 28A of the present configuration, the degree of freedom of the joining form with the members to be joined to these is improved. it can. For example, in the boss portion 45, a female screw portion 56 is formed on the inner peripheral portion of the connecting member 57A, and a male screw portion 58 is formed on the outer peripheral portion. As a result, it is possible to realize joining with the member to be joined by using both the female screw portion 56 and the male screw portion 58. Therefore, the degree of freedom in designing the boss portion 45 can be improved, and the connection strength and the connection position accuracy can be further improved.

The housing portion 27 having the hollow cylindrical portion 31 as described above, the first housing portion 28 which is a pinion housing on one end side in the axial direction of the hollow cylindrical portion 31, and the second housing portion 32 on the other end side in the axial direction It is composed of a composite material of a fiber material (for example, carbon fiber) and a resin material (for example, epoxy resin). The fiber material is embedded in the resin material, but a part of the fiber material is exposed on the surface of the resin material. The housing portion 27 is excellent in mechanical properties because there is no sheet interface and the reinforcing fibers and the resin material are uniformly dispersed throughout the product. Further, in order to make a composite material of carbon fiber (specific gravity 1.8) and epoxy resin (specific gravity 1.4), it is possible to provide a housing portion 27 that is lighter than the conventional aluminum (specific gravity 2.7) material. It will be possible.

As the resin material used for the composite material, a thermoplastic resin or a thermosetting resin can be used. As the thermoplastic resin, for example, polyamide 6 can be used. As the thermosetting resin, for example, an epoxy resin or a phenol resin can be used.

The fiber material used for the composite material is selected from at least one of glass fiber, carbon fiber, metal fiber, aramid fiber, aromatic polyamide fiber, liquid crystal polyester fiber, silicon carbide fiber, alumina fiber, and boron fiber. be able to.

In particular, glass fiber and boron fiber are preferable because of their high tensile strength. Carbon fiber is excellent in wear resistance, heat resistance, thermal elasticity, acid resistance, and electrical conductivity. As the metal fiber, a metal thread such as stainless steel, aluminum, iron, nickel, or copper can be used. Aramid fiber has strong tensile strength and frictional resistance, and is also excellent in high temperature and chemical resistance. Aromatic polyamide fibers have very good heat resistance and strength. Liquid crystal polyester fibers have higher rigidity than engineering plastics reinforced with fillers even in the non-reinforced state. Alumina fiber can be used even in a high temperature range and has fire resistance.

The fiber material in the composite material has a random fiber orientation direction, and a part of the fiber material is exposed at the interface with the connecting member. The average fiber length of the fiber material can be 0.5 mm or more and 50.8 mm (2 inch) or less.

For example, when carbon fiber is used as the fiber material, one having an average fiber length of 0.5 mm or more is preferable. The average fiber length is preferably 0.7 mm or more, more preferably 1 mm or more. By setting the average fiber length of the fiber material to 0.5 mm or more, the reinforcing effect of the resin material in the composite material can be surely obtained. The average fiber length is preferably 50.8 mm or less. By setting the average fiber length of the fiber material to 50.8 mm or less, the fiber material can be smoothly opened in the solvent without being entangled with the stirrer in the manufacturing process described later, and the composite material can be made more homogeneous.

The amount of carbon fiber blended in the resin composition is preferably 10 to 60% by weight. When it is necessary to further improve the mechanical strength, it is advisable to increase the amount of carbon fiber compounded or to mix carbon fibers having different average fiber lengths. It is also necessary to adjust the average fiber length and the fiber compounding amount of the composite material in consideration of toughness, and by setting the above range, good mechanical properties can be obtained.

An adhesive layer is formed at each interface between the boss portions 33, 35, 37, 39, 45, 47 of the housing portion 27 and the connecting members 49, 51, 53, 55, 57, 59 described above. The boss portion and the connecting member may be adhered to each other by this adhesive layer. As the adhesive for forming the adhesive layer, polyvinyl alcohol, phenol resin, epoxy resin and the like can be used.

The housing portion 27 having the above configuration is entirely made of a composite material except for the connecting members 49, 51, 53, 55, 57, 59. However, the present invention is not limited to this, and appropriate changes can be made such that at least only the first housing portion 28 and the second housing portion 32 are made of a composite material.

Next, a method of manufacturing the rack and pinion housing 100 will be described.
5 (A) to 5 (F) are process diagrams illustrating a manufacturing process of the rack and pinion housing.
The manufacturing process of the rack and pinion housing includes a fiber material opening process, a preform molding process, an assembly process of assembling a connecting member to the molded preform, and a resin molding molding process. Have in order.

In the fiber-spreading step, as shown in FIG. 5 (A), a large number of billets 61 containing carbon fibers as a fiber material are put into a container 62 containing the solvent 74, and a stirrer 63 is driven into the solvent. To open the carbon fiber of.

As a result, as shown in FIG. 5 (B), a homogeneous fiber-containing slurry 65 is obtained. As the solvent, water (white water) is preferable from the viewpoint of stability, handleability, and cost, but in addition, a solvent such as ethanol or methanol or a mixed system thereof may be used.

Subsequently, in the papermaking step, as shown in FIG. 5C, the fiber-containing slurry 65 is sealed together with the molding core metal 87 in the papermaking mold 67 for housing molding. A suction pump (not shown) is connected to the discharge pipe 66 provided in the papermaking mold 67. Further, a papermaking net 68 is arranged on the mold surface of the papermaking mold 67 along the shape of the mold. When the suction pump discharges air or the solvent of the fiber-containing slurry 65 to the outside of the mold through the discharge pipe 66, the fiber laminate is manufactured on the papermaking net 68 arranged in the papermaking mold 67. Then, the wet fiber laminate obtained after papermaking is solidified by a drying treatment.

As a result, as shown in FIG. 5 (D), a hollow preform 69 having substantially the same shape as the finished product is formed from the drafting mold 67. The papermaking mold 67 is not limited to this, and for example, the finished product may be made by making a semi-cylindrical preform obtained by dividing the finished product into two by a plane including the axis. In that case, the obtained semi-cylindrical preforms may be joined to finally form the hollow preform 69 shown in FIG. 5 (D). In the illustrated example, for the sake of simplicity, the shape in which only the boss portion 33 is provided is illustrated. The other boss portions 35, 37, 39, 45, 47 are the same as the boss portion 33, and thus the description thereof will be omitted.

Next, in the assembling step, as shown in FIG. 5 (E), the connecting member 49 is assembled to the boss portion 33 formed in the hollow preform 69.

Then, in the molding step, as shown in FIG. 5 (F), the hollow preform 69 to which the connecting member 49 is assembled is loaded into the molding mold 71 together with the molding core metal 89, and the plunger gear pump or the like is loaded. A resin material 73, which is a mixture of a main agent such as a thermoplastic resin or an epoxy resin and a curing agent, is injected into the mold at a constant pressure by a material supply unit 72 as a driving source.

Here, it is preferable to preheat the molding die 71 before injecting the resin material 73 into the molding die 71. More preferably, it is preheated together with the molding core metal 89. In that case, since the resin material 73 is uniformly heated, molding defects are less likely to occur, the curing time can be shortened, and productivity is improved.

Further, it is preferable to use an adhesive together for joining the metal connecting member 49 and the boss portion 33 in the step of FIG. 5 (E). Specifically, the connecting member 49 is attached to the boss portion 33 in which the adhesive is infiltrated by applying the adhesive to the boss portion 33 of the preform 69. As a result, the connecting member 49 is adhered to the boss portion 33. By carrying out the molding process in that state, the connecting member 49 is firmly fixed to the boss portion 33 by the resin. As a result, the joint strength between the connecting member 49 and the boss portion 33 can be further improved.

As described above, the assembling step may include a step of applying an adhesive to the surface of the boss portion 33 in advance and fixing the connecting member 49 to the boss portion 33 with the adhesive. The adhesive may be a thermosetting resin, and is not particularly limited as long as it is an epoxy resin or a resin having an affinity for other substances.

Further, in a composite material composed of an epoxy resin as a resin material and a carbon fiber as a fiber material, in order to improve the strength of the composite material, the adhesion between the resin material and the fiber material and the fiber dispersibility should be improved. Is preferable. Therefore, the fiber material may be adhered with epoxy, urethane, or a sizing agent. The sizing agent can be appropriately selected in consideration of the reaction between the organic functional group and the resin or elastomer.

Various additives may be added to the resin material for molding within a range that does not impair the object of the present invention. Examples of the additive include solid lubricants such as graphite, hexagonal boron nitride, fluorine mica, ethylene tetrafluoride resin powder, tungsten disulfide, and molybdenum disulfide, inorganic powder, organic powder, lubricating oil, and plasticizer. Rubber, antioxidants, heat stabilizers, UV absorbers, light protectants, flame retardants, antistatic agents, mold release agents, fluidity improvers, thermal conductivity improvers, non-adhesive imparts, crystallization accelerators , Nucleating agents, pigments, dyes and the like can be exemplified.

In the molding die 71, after the injected resin material 73 is cured, the composite product in which the preform 69 and the connecting member 49 are integrally molded is taken out from the molding die 71 together with the molding core metal 89, and the composite product Remove the molding core metal 89 from. As a result, a rack and pinion housing 100 in which the connecting member 49 is integrated with the preform 69 by the resin material 73 is obtained.

Next, the operation of the rack and pinion housing 100 obtained by the above manufacturing method will be described.
In the rack and pinion housing 100 having this configuration, a cylindrical boss portion 33 is formed on a preform 69 which is a precursor made of a fiber material. A metal connecting member 49 is fitted into the inner peripheral portion of the cylinder of the boss portion 33, so that the outer peripheral portion of the connecting member 49 is brought into close contact with the inner peripheral portion of the cylinder. Then, by molding the preform 69 made of the fiber material to which the connecting member 49 is attached as the insert material, the resin material is impregnated in the gap of the fiber material. The connecting member 49 is integrated with the preform 69 (fiber material) by the impregnated resin material.

FIG. 6A is a cross-sectional view showing a joint portion between the boss portion 33 and the connecting member 49 in which the connecting member 49 is assembled to the boss portion 33, and FIG. 6B is a cross-sectional view showing the joint portion between the boss portion 33 and the connecting member 49 after molding. It is sectional drawing which showed the joint part with 49.

As shown in FIG. 6A, a large number of fiber materials 75 are brought into close contact with the connecting member 49 by assembling the connecting member 49 to the fiber material 75 of the boss portion 33. Moreover, since the fiber orientation direction of the fiber material 75 is randomly oriented by papermaking, the contact direction of each fiber with the connecting member 49 is also random.

Then, as shown in FIG. 6B, when the resin material 73 is impregnated in the gaps between the fiber materials 75 by the molding process, the connecting member 49 and the boss portion 33 are joined by the resin material 73. At the joining interface 76 between the connecting member 49 and the boss portion 33, a part of the fiber material 75 is in close contact with the connecting member 49. Further, on the boss portion 33 side, the fiber material 75 is in a state of being evenly dispersed and arranged in the resin matrix.

Here, a reference example is shown in FIG. FIG. 7 is a cross-sectional view showing a joint portion in which the housing portion 27A including the fiber material 75 is joined to the connecting member 49A by the adhesive 79. In the case of this reference example, the connecting member 49A and the housing portion 27A are joined via an adhesive 79. Since the adhesive 79 cannot enter the housing portion 27A containing the fiber material 75, it becomes a fragile layer 81 weaker than the housing portion 27A and is interposed with the connecting member 49A. Therefore, when the housing portion 27A or the connecting member 49A receives a large external force, the fragile layer 81 may become a peeling surface and may be destroyed.

On the other hand, in the joining structure of the present configuration shown in FIG. 6B, in the boss portion 33, the resin material 73 covers the connecting member 49, and a part of the fiber material 75 is exposed and connected to the joining interface 76. It is in close contact with the member 49, and in this state, the resin material 73 is impregnated between the fiber materials 75. As a result, the boss portion 33 of the housing portion 27 is firmly joined to the connecting member 49 by the resin material 73 without having a fragile portion. Moreover, since the fiber material 75 is arranged up to the joining interface 76, peeling between the connecting member 49 and the boss portion 33 at the joining interface 76 is unlikely to occur. Further, since the fiber materials 75 are randomly arranged, the strength against an external force from an arbitrary direction can be improved. Further, since the composite material composed of the resin material 73 and the fiber material 75 has a single-layer structure, there is no interface inside the composite material. Therefore, the interfacial peeling between the carbon fiber sheets in the composite material, which has been conventionally generated, does not occur, and the bonding strength can be maintained high.

Further, the fiber material 75 has an average fiber length of 0.5 mm or more and 50.8 mm or less. Therefore, the fiber material 75 can be smoothly opened in the solvent, the uniform preform 69 in which the fiber material 75 is evenly dispersed is formed, and the reinforcing effect of the resin material 73 by the fiber material 75 after molding is ensured. It is possible to obtain both.

Next, a case where the connecting member 49 is assembled to the boss portion 33 coated with the adhesive will be described in the assembling step prior to the molding step described above.
FIG. 8A is a cross-sectional view showing a joint portion between the boss portion 33 and the connecting member 49 in which the connecting member 49 is assembled to the boss portion 33 coated with the adhesive 79, and FIG. 8B is a boss after molding. It is sectional drawing which showed the joint part of part 33 and connection member 49.

According to this configuration, as shown in FIG. 8A, the connecting member 49 is adhered to the boss portion 33 by the adhesive 79 impregnated in the gap between the fiber materials 75 of the boss portion 33. The adhesive layer formed at the bonding interface 76 becomes the composite adhesive layer 83 in which the fiber material 75 is present, and high bonding strength can be obtained. After that, the resin material 73 is impregnated in the gaps between the fiber materials on the outside of the composite material adhesive layer 83 in the molding process.

As shown in FIG. 8B, when the resin material 73 is impregnated in the gaps between the fiber materials 75 of the boss portion 33, the fiber material 75 outside the composite material adhesive layer 83 is a composite material covered with the resin material 73. It becomes layer 85. Both the composite material adhesive layer 83 and the composite material layer 85 are layers of the composite material in which the fiber material 75 is randomly oriented. Since the adhesive 79 has a higher adhesive force with the connecting member 49 than the resin material 73, the composite adhesive layer 83 is stronger than the case shown in FIG. 6 (B) described above. 49 is adhesively fixed. As a result, the bonding strength of the connecting member 49 to the housing portion 27 is further improved as compared with the case of bonding with the resin material 73. Further, the bonding strength with the connecting member 49 is improved as the material has a higher affinity between the composite adhesive layer 83 and the resin material 73.

Also in this configuration, the strength against an external force from an arbitrary direction can be improved without peeling at the bonding interface 76. Further, since it is composed of a composite material made of a resin material 73 and a fiber material 75, a lightweight and high-strength rack and pinion housing 100 can be obtained.

In the rack and pinion type steering device including the rack and pinion housing 100 having each configuration described above, the housing portion is composed of a composite material of a resin material and a fiber material, and the housing portion made of the composite material and the connecting member are used. No fragile layer is formed at the joint interface of the housing. Therefore, a decrease in joint strength between the connecting member and the housing portion can be suppressed. Further, since the fiber material is uniformly dispersed in the housing portion in a random orientation direction, it is less likely to be damaged even if it receives an impact from the outside, and the rack and pinion of the EPS reduction gear can be reliably protected. Further, since the housing portion is made of a composite material, the weight can be reduced as compared with a conventional housing made of die-cast aluminum or the like. Further, as described above, according to the rack and pinion type steering device having this configuration, it is possible to reduce the weight while ensuring the necessary strength and rigidity.

The present invention is not limited to the above-described embodiment, and can be modified or applied by those skilled in the art based on the combination of the configurations of the embodiments with each other, the description of the specification, and well-known techniques. It is the planned invention and is included in the scope of seeking protection.

As described above, the following matters are disclosed in this specification.
(1) A rack and pinion including a rack and pinion having a rack shaft having rack teeth and a pinion meshed with the outside of the rack and pinion, and a joint portion formed in a part of the housing portion to which a member to be joined is connected. A pinion housing, wherein the housing portion includes a composite material of a fiber material and a resin material, and the joint portion includes a boss portion made of the composite material and a connecting member fixed to the boss portion. The rack and pinion housing is characterized in that the fiber orientation direction is random, and a part of the fiber material in the boss portion is exposed at an interface with the connecting member.
According to this rack and pinion housing, since the housing portion is formed of a composite material made of a fiber material and a resin material, the connecting member can be attached to the boss portion without passing through a fragile layer. That is, the boss portion of the housing portion is filled with the resin material up to the bonding interface with the connecting member. Further, a part of the fiber material is exposed at the joining interface with the connecting member and adheres to the connecting member. Therefore, the fragile layer in which the fiber material does not exist does not exist at the interface of the housing portion with the connecting member. Therefore, peeling does not occur between the connecting member and the housing, and a high-strength connection structure can be obtained.

(2) The fiber material is selected from at least one of glass fiber, carbon fiber, metal fiber, aramid fiber, aromatic polyamide fiber, liquid crystal polyester fiber, silicon carbide fiber, alumina fiber and boron fiber. The rack and pinion housing of (1), which is characterized by being present.
According to this rack and pinion housing, by mixing the above fiber material with a resin material and solidifying it, lighter weight and sufficient strength can be obtained as compared with metal.

(3) The rack and pinion housing according to (1) or (2), wherein the average fiber length of the fiber material is 0.5 mm or more and 50.8 mm or less.
According to this rack and pinion housing, the fiber material can be smoothly opened in a solvent to form a homogeneous preform, and the effect of reinforcing the resin material by the fiber material after molding can be surely obtained at the same time. ..

(4) The rack and pinion housing according to any one of (1) to (3), wherein an adhesive layer is formed at an interface between the connecting member and the boss portion.
According to this rack and pinion housing, the connecting member is adhered to the boss portion by an adhesive before the gaps between the fiber materials are impregnated with the resin material. As a result, the connecting member can be more strongly fixed to the boss portion. Further, in the molding process, the positional deviation between the connecting member and the housing does not occur.

(5) The rack and pinion housing according to (4), wherein the adhesive layer contains at least one of polyvinyl alcohol, phenol resin, and epoxy resin.
According to this rack and pinion housing, the affinity between the resin material impregnated in the gaps between the fibrous materials and the adhesive that adheres the connecting member to the boss portion can be ensured, and the bonding strength between the connecting member and the housing can be improved. Can be enhanced.

(6) The rack and pinion housing according to any one of (1) to (5), wherein the resin material is a thermoplastic resin or a thermosetting resin.
According to this rack and pinion housing, by using the thermoplastic resin, the curing time is not required, and the housing can be manufactured in a short time. Further, by using a thermosetting resin, the heat resistance of the housing can be improved because it is not deformed or melted even if it is heated again.

(7) The rack and pinion housing according to any one of (1) to (6) and
A rack shaft having rack teeth on at least a part of the outer circumference and being reciprocally supported by the rack and pinion housing.
A pinion shaft attached to the lower end of the steering shaft, rotatably supported by the rack and pinion housing, and having a pinion that meshes with the rack teeth of the rack shaft.
Have,
A rack-and-pinion type steering device that reciprocates the rack shaft by rotation of the pinion shaft and steers wheels via a tie rod.
According to this rack and pinion type steering device, since the rack and pinion housing covering the rack shaft is composed of a composite material of a resin material and a fiber material, it is stronger than a conventional housing made of, for example, an aluminum die-cast product. It is possible to reduce the weight while maintaining the above.

(8) The fabrication mold is obtained by opening the fiber material in a solvent to obtain a fiber-containing slurry, and by injecting the fiber-containing slurry into a fabrication mold and removing the solvent from the inside of the fabrication mold. A manufacturing process for molding a preform having almost the same shape as the finished product, an assembling step for assembling a connecting member to the boss portion formed on the preform, and a molding process for assembling the preform to which the connecting member is assembled. A method for manufacturing a rack and pinion housing, which comprises a molding step of loading into a mold and integrally molding the preform and the connecting member with a resin.
According to this rack and pinion housing manufacturing method, the fiber-containing slurry obtained in the fiber-spreading step is sealed in a preform manufacturing mold and dried in the baking step. The fibers taken out from the molding mold are made into a preform having almost the same shape as the finished product, and a metal connecting member is attached to a part of the boss portion of the preform. That is, the connecting member is in close contact with the boss portion made of the fiber material. The preform is placed in the molding mold in this state and the resin is injected. Therefore, the rack and pinion housing taken out from the molding die is in a state of being firmly integrally molded with the resin material in a state where the connecting member is in close contact with a part of the fiber material. Therefore, the joint strength between the connecting member and the boss portion can be improved.

(9) The method for manufacturing a rack and pinion housing according to (8), wherein the assembling step includes a step of fixing the connecting member to the boss portion with an adhesive.
According to this rack and pinion housing manufacturing method, after molding the preform, the connecting member is fixed to the boss portion of the preform with an adhesive. As a result, the joint strength between the connecting member and the boss portion is further improved.

10 Rack and pinion type steering device 21 Tie rod 23 Rack shaft 25 Pinion shaft 27 Housing part 29 Joint part 33, 35, 37, 39, 45, 47 Boss part 49, 51, 53, 55, 57, 59 Connection member 65 Fiber Containing slurry 67 Extraction mold 69 Preform 71 Molding mold 73 Resin material 75 Fiber material 79 Adhesive 100 Rack and pinion housing

Claims (2)

A fiber material selected from at least one of glass fiber, carbon fiber, aramid fiber, aromatic polyamide fiber, liquid crystal polyester fiber, silicon carbide fiber, and boron fiber is opened in a solvent to obtain a fiber-containing slurry. Textile process and
A papermaking step of injecting the fiber-containing slurry into a papermaking mold and removing the solvent from the papermaking mold to form a preform having substantially the same shape as the finished product from the papermaking mold.
Assembling process of assembling the connecting member to the boss portion formed on the preform,
A molding step of loading the preform to which the connecting member is assembled into a molding mold and integrally molding the preform and the connecting member with a resin.
A method of manufacturing a rack and pinion housing, which comprises. The method for manufacturing a rack and pinion housing according to claim 1 , wherein the assembling step includes a step of fixing the connecting member to the boss portion with an adhesive.

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