JP2005140140A - Resinous bevel gear and its processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To contrive a reinforcement fiber base material of an annular resin forming body so as to improve the durability, in a resinous bevel gear in which a tooth is imparted on the annular resin forming body integrated with the periphery of a metal bushing. <P>SOLUTION: The annular resin forming body 2 is formed to hold the resin in a cylinder wound with the belt-shaped reinforcement fiber base material. The axial direction of the cylinder is conformed to the rotational axis direction of the gear. The tooth 3 is imparted to the axial end of the cylinder. The bevel gear is processed by the following process : (1) preparing of belt-shaped reinforcement fiber base material. (2) winding of belt-shaped reinforcement fiber base material around the periphery of the metal bushing 1 to form the cylinder. (3) storing of metal bushing 1 and the cylinder, impregnating of cylinder with the resin, and forming of the annular resin forming body integrated with the metal bushing, holding the shape of the cylinder substantially. (4) gear cutting at the axial end of the annular resinous forming body. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a resin bevel gear suitable for automobile parts and the like, and a method for manufacturing the same.

  Resin gears are used as counterpart gears that mesh with metal gears in order to suppress noise generation when teeth are engaged, and are required to have wear resistance and high strength.

2. Description of the Related Art Conventionally, a resin gear has been proposed in which teeth are processed into an annular resin molded body in which a reinforcing fiber base is impregnated with a resin. For example, it is the following technique disclosed in Patent Document 1.
A tubular body woven or knitted with a bundle of reinforcing fibers is prepared. This cylindrical body is wound up in the axial direction from the end portion to form an annular reinforcing fiber base material. And an annular reinforcement fiber base material and the metal bush arrange | positioned in the center are accommodated in a shaping die. The molding die opens and closes in the direction of the thickness of the annular reinforcing fiber base. The annular reinforcing fiber, which is expanded radially by compressing the annular reinforcing fiber by closing the molding die, is pressed around the metal bush. Then adjust to the shape. Next, a liquid resin is injected into the closed molding die, and the liquid resin infiltrated into the annular reinforcing base material is heated and cured to form an annular resin molded body using a metal bush as an insert. Then, teeth are formed by cutting on the outer peripheral surface of the resin molded body.

Japanese Patent Laid-Open No. 08-156124

The conventional technique is used for a spur gear or a helical gear. Since the annular reinforcing fiber base material undergoes a process of being compressed in the thickness direction, the stacking direction of the base materials is substantially coincident with the thickness direction of the metal bush. In the case of a spur gear or a helical gear, such a configuration is a strength surface because the direction of the load applied to the teeth formed on the peripheral surface of the annular resin molded product intersects the surface direction of the base material layer. It can be said that it is ideal.
However, when the bevel gear is configured by applying this technique, teeth are formed on the axial end face of the annular resin molded body, and the load direction applied to the teeth increases as the shaft angle of the gear increases. It becomes almost parallel to the surface direction of the base material layer, and is not optimal in terms of strength and durability.

  The problem to be solved by the present invention is to improve the durability of the resin bevel gear by devising the configuration of the reinforcing fiber base.

The resin bevel gear according to the present invention is obtained by providing teeth to an annular resin molded body integrated with the outer periphery of a metal bush, and has the following configuration in order to solve the above problems.
That is, it is characterized by this.

The resin bevel gear having the above configuration is manufactured by the following method.
The first production method is characterized by going through the following steps (1) to (4).
(1) A step of preparing a belt-shaped reinforcing fiber base material.
(2) A step of forming a cylindrical body by winding the belt-shaped reinforcing fiber base material on the outer periphery of a metal bush.
(3) The metal bush and the cylindrical body are accommodated in a molding die, the cylindrical body is impregnated with a resin, and heated and pressed or thermoformed, and the cylindrical body substantially maintains its shape. A step of obtaining an annular resin molded body integrated with the metal bush as it is.
(4) A step of gear cutting on the axial end surface of the resin molded body.

  In the first manufacturing method, both axial end surfaces of the cylindrical body formed in the step (2) are made higher than both surfaces of the metal bush, and the metal bush and the cylindrical body are formed in the step (3). When accommodated in a mold, the cylindrical body is preferably compressed in its axial direction. Of course, it is a premise that the cylindrical body substantially maintains its shape even by the axial compression.

The second production method is characterized by going through the following steps (1) to (4).
(1) A step of preparing a prepreg in which a belt-shaped reinforcing fiber base material is impregnated with a resin to be in a semi-cured state.
(2) A step of forming a cylindrical body by winding the prepreg over the outer periphery of a metal bush while applying heat and pressure.
(3) A step of obtaining an annular resin molded body in which the cylindrical body is integrated with a metal bush while the cylindrical body is substantially maintained in shape while the cylindrical body is heated or thermoformed or heat-pressurized. .
(4) A step of gear cutting on the axial end surface of the resin molded body.

  As described above, the resin bevel gear according to the present invention is provided with teeth on the axial end face of a cylindrical body formed by overlappingly winding a belt-shaped reinforcing fiber base material. Therefore, the direction of the load applied to the teeth intersects with the axial direction of the cylindrical body, which is ideal in terms of strength. Since the reinforcing fiber base material is laminated in a direction stronger than the load direction applied to the teeth of the bevel gear, the durability of the gear can be expected to be improved.

Usually, a rotation stopper is protruded from the peripheral surface of the metal bush and is bitten into the annular resin molded body, thereby strengthening the integration of the metal bush and the annular resin molded body. In the first manufacturing method according to the present invention, the reinforcing fiber base material is bitten into the detent in the step of forming a cylindrical body by winding the belt-shaped reinforcing fiber base material around the outer periphery of the metal bush. Here, it is preferable that the width of the belt-shaped reinforcing fiber base is slightly widened and both end surfaces in the axial direction of the cylindrical body formed in the step (2) are made higher than both surfaces of the metal bush. If the relationship between the metal bush and the cylindrical body is configured as described above, the cylindrical body can be compressed in the axial direction when it is accommodated in the molding die in the step (3), and the detent is prevented. Can be more reliably bitten into the layer of the reinforcing fiber base.
However, the compression is performed so that the cylindrical body can substantially maintain its shape. The cylindrical body is greatly deformed by the compression, and if the laminated structure in which the reinforcing fiber base material is overwrapped is disturbed, the reinforcing base material does not effectively act against the load applied to the teeth, so that excessive compression is avoided. To do.

  In the second production method, in the step (2), the strip-shaped prepreg is overwrapped while applying heat and pressure to the outer periphery of the metal bush to form a cylindrical body, so that the resin in the prepreg softens and rotates. The stop can be satisfactorily dig into the layer of the reinforcing fiber base. Therefore, in the step (3), the cylindrical body may be heated to cure the resin. Or, if necessary, heat molding or heat pressure molding is performed.

Embodiments of the present invention will be described with reference to the drawings.
The reinforcing fiber base is composed of polyester, fluororesin, para aromatic polyamide, meta aromatic polyamide, organic fibers such as carbon, and inorganic fibers such as glass and stainless steel. The band-shaped reinforcing fiber base material is formed by mechanically connecting the fibers with a cloth woven with the spun yarn of the fiber (for example, a plain woven cloth) or with fibers that are needle-punched to a fiber accumulation body and oriented in the thickness direction. It is an intertwined felt. This belt-shaped reinforcing fiber base material may be manufactured with a predetermined band width from the beginning, or a wide and prepared one may be cut into a predetermined band width.

  In the resin bevel gear according to the present invention, as shown in a cross-sectional view in FIG. 1, teeth 3 are provided on an annular resin molded body 2 integrated with the outer periphery of a metallic bush 1. The annular resin molded body 2 has a configuration in which a resin is held in a cylindrical body formed by laminating a belt-shaped reinforcing fiber base material. A plurality of longitudinal lines drawn in the annular resin molded body 2 in FIG. 1 schematically show a longitudinal section of a tubular body formed by overlapping and winding a belt-shaped reinforcing fiber base material. The axial direction of the cylindrical body coincides with the rotational axis direction of the bevel gear, and the teeth 3 are provided on the axial end surface of the cylindrical body. A rotation stopper 4 projecting radially from the outer peripheral surface of the metal bush 1 bites into the inner peripheral surface of the annular resin molded body 2, and the combined integration of the metal bush 1 and the annular resin molded body 2 is strong. I have to. Examples of the resin held in the cylindrical body include cross-linked polyaminoamide, epoxy, and polyimide.

The gear is manufactured by the following process (first manufacturing method).
FIG. 2 shows an example of the metal bush 1 in a plan view (a) and a sectional view (b). On the outer peripheral surface of the metal bush 1, rotation stoppers 4 protruding in the radial direction are provided at regular intervals. As shown in FIG. 3, a strip-shaped reinforcing fiber base material 5 is overlapped and wound around the outer peripheral surface of the metal bush 1 to form a cylindrical body having a predetermined thickness. The wrapping of the reinforcing fiber base 5 is performed so that the metal bush 1 is tightened, and the rotation stopper 4 is bitten into the formed cylindrical body. The band-shaped reinforcing fiber base 5 is preferably 1.2 to 1.5 times larger in width than the thickness of the metal bush 1. FIG. 3B shows such a configuration, and both end surfaces in the axial direction of the cylindrical body are higher than both surfaces of the metal bush 1.

  As shown in FIG. 4, the metal bush 1 and a band-shaped reinforcing fiber base material 5 made of a cylindrical body are accommodated in a molding die 6. When the molding die 6 is closed, both end faces of the cylindrical body formed by wrapping the reinforcing fiber base material 5 are compressed in the axial direction. In the example shown in FIG. 4, the both end surfaces of the cylindrical body are compressed until they are flush with both surfaces of the metallic bush 1. As a result, the detent 4 is securely cut into the layer of the reinforcing fiber base 5. This compression operation causes a slight disturbance in the layer of the reinforcing fiber base 5 constituting the cylindrical body, but the degree of tightening during lap winding so that the cylindrical body can substantially maintain its shape. The height of the cylindrical body and the degree of compression when accommodating the molding die are adjusted.

  After the metal bush 1 and the tubular reinforcing fiber base material 5 in the form of a cylindrical body are accommodated in the molding die 6, the molding space is degassed and decompressed, and then the liquid resin 7 is injected into the molding space. Then, it penetrates into the layer of the reinforcing fiber base 5. And it heat-molds or heat-press-molds, and obtains the cyclic | annular resin molded object 2 integrated with the metal bushes 1 with the cylindrical body substantially maintaining the shape. The volume filling rate of the reinforcing fiber base 5 in the annular resin molded body 2 is set to 30 to 60% in consideration of substantial maintenance of the cylindrical body shape, moldability, gear cutting workability described below, and the like. preferable.

  Gear cutting is performed on the axial end surface of the annular resin molded body 2 formed as described above to obtain a predetermined bevel gear. In the bevel gear shown in FIG. 1, the surface of the metallic bush 1 on the side to which the teeth 3 are applied is partially removed by cutting to reduce the thickness, and the inner peripheral side of the teeth 3 is smaller than the surface of the metallic bush 1. It is high. In FIG. 1, this is why the rotation stopper 4 is not located in the center of the metal bush 1 in the thickness direction but is located closer to the teeth 3.

The bevel gear according to the present invention can also be manufactured by the following method (second manufacturing method).
A prepreg prepared by impregnating a belt-shaped reinforcing fiber base material with a thermosetting resin and drying to make a semi-cured state is prepared. The prepreg is overwrapped while applying heat and pressure to the outer periphery of the metal bush to form a cylindrical body. At this time, since the resin in the prepreg is softened, it is possible to satisfactorily bite the rotation stopper into the layer of the reinforcing fiber base. This is cured by heating as it is to obtain an annular resin molded body integrated with a metal bush. Or you may heat-press-mold in a shaping die. The width dimension of the band-shaped reinforcing fiber base is appropriately adjusted in relation to the thickness of the metal bush. Hereinafter, similarly to the above-described embodiment, the axial end surface of the annular resin molded body is subjected to gear cutting to obtain a predetermined bevel gear.

Example 1
A plain weave fabric having a unit mass of 130 g / m ² is prepared using a yarn obtained by blending para-aramid fibers and meta-aramid fibers at a weight ratio of 50/50. This cloth is cut at a predetermined width (1.2 times the thickness of the metal bush) to form a belt-like reinforcing fiber base. A resin bevel gear was manufactured by using the belt-shaped reinforcing fiber base material by the first manufacturing method described above. The resin constituting the cyclic resin molded body was a crosslinked polyaminoamide.
This bevel gear has an axial angle of 90 ° and teeth substantially on the end face in the axial direction of the annular resin molded body.

Example 2
Needle punching is performed on a laminated body in which para-aramid fibers and meta-aramid fibers are accumulated at a weight ratio of 50/50 to prepare a felt having a unit mass of 130 g / m ² . This felt is cut to a predetermined width (1.2 times the thickness of the metal bush) to form a belt-like reinforcing fiber base. A resin bevel gear was manufactured by using the belt-shaped reinforcing fiber base material by the first manufacturing method described above. The resin constituting the cyclic resin molded body was a crosslinked polyaminoamide.
This bevel gear has an axial angle of 90 ° and teeth substantially on the end face in the axial direction of the annular resin molded body.

Conventional Example 1
A resin bevel gear was manufactured according to the conventional technique described in Background Art. Except for the difference in the configuration of the reinforcing fiber substrate, the production was carried out generally in accordance with the examples according to the present invention.
In this resin bevel gear, as shown in FIG. 5, the lamination direction of the reinforcing fiber base material substantially coincides with the thickness direction of the metal bush. A plurality of horizontal lines drawn in the annular resin molded body 2 in FIG. 5 schematically show a longitudinal section of the layer of the reinforcing fiber base.

Conventional example 2
In Example 2, a resin bevel gear was manufactured using an annular reinforcing fiber base material obtained by crushing a cylindrical body formed by wrapping felt in a bellows shape in the axial direction. This resin bevel gear has a configuration in which the lamination direction of the reinforcing fiber base further matches the thickness direction of the metal bush.

  A durability evaluation test (rotating at 240 rpm with a load of 28 N · m) of each of the resin bevel gears described above was performed, and the time until failure was compared. The results are shown in Table 1.

It is sectional drawing which shows the example of the resin bevel gears concerning this invention. It is the top view and sectional drawing which show the example of metal bushes used in the Example of this invention. In the Example of this invention, it is the top view and sectional drawing which show the state which wound the strip | belt-shaped reinforcement wire base material on the outer periphery of metal bushes. In the Example of this invention, it is cross-sectional explanatory drawing which shows the state which shape | molds the cylindrical body comprised by overlappingly winding a strip | belt-shaped reinforcement fiber base material with metal bushes. It is sectional drawing which shows the example of the conventional resin bevel gears.

Explanation of symbols

1: Metal bush 2: Cyclic resin molded body 3: Teeth 4: Detent 5: Belt-shaped reinforcing fiber base 6: Mold 7: Liquid resin

Claims (5)

In the bevel gear in which teeth are given to the annular resin molded body integrated with the outer periphery of the metal bush,
The annular resin molded body has a configuration in which a resin is held in a cylindrical body formed by wrapping a belt-shaped reinforcing fiber base material, the axial direction of the cylindrical body coincides with the rotational axis direction of the gear, and the teeth are cylindrical. A resin bevel gear, which is provided on an end surface in the axial direction of a cylindrical body. A method for producing a resin bevel gear, characterized by undergoing the following steps (1) to (4).
(1) A step of preparing a belt-shaped reinforcing fiber base material.
(2) A step of forming a cylindrical body by winding the belt-shaped reinforcing fiber base material on the outer periphery of a metal bush.
(3) The metal bush and the cylindrical body are accommodated in a molding die, the cylindrical body is impregnated with a resin, and heated and pressed or thermoformed, and the cylindrical body substantially maintains its shape. A step of obtaining an annular resin molded body integrated with the metal bush as it is.
(4) A step of gear cutting on the axial end surface of the resin molded body.   When both axial end surfaces of the cylindrical body formed in the step (2) are made higher than both surfaces of the metal bush, and the metal bush and the cylindrical body are accommodated in the molding die in the step (3), the cylindrical body The method of manufacturing a resin bevel gear according to claim 2, wherein the body is compressed in the axial direction. A method for producing a resin bevel gear, characterized by undergoing the following steps (1) to (4).
(1) A step of preparing a prepreg in which a belt-shaped reinforcing fiber base material is impregnated with a resin to be in a semi-cured state.
(2) A step of forming a cylindrical body by winding the prepreg over the outer periphery of a metal bush while applying heat and pressure.
(3) A step of obtaining an annular resin molded body in which the cylindrical body is integrated with a metal bush while the cylindrical body is substantially maintained in shape while the cylindrical body is heated or thermoformed or heat-pressurized. .
(4) A step of gear cutting on the axial end surface of the resin molded body.   The belt-shaped reinforcing fiber base material is a cloth woven from yarns bundled with reinforcing fibers, or a felt obtained by applying needling to an accumulation layer of reinforcing fibers and bonding reinforcing fibers facing in a plane direction. 4. A method for producing a resin bevel gear according to any one of 4 above.

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