JP6156695B2 - Gear device - Google Patents

Description

  The present invention relates to a gear device.

Conventionally, many of the gears used in automobiles have been made of metal parts in terms of strength and heat resistance. However, in recent years, the development of environment-friendly automobiles has progressed, and the weight has been reduced to improve fuel economy and reduce CO ₂ emissions. Furthermore, from the viewpoint of quietness of the meshing sound between the metal gears, it is suggested to use a resin gear.

As a specific configuration of the resin gear, there is one using an aramid fiber as a reinforcing fiber base, and a reinforcing fiber base 1 formed in a donut shape as shown in FIG. The base material 1 is impregnated with resin and cured to produce a circular material 3. Patent Document 1 describes a method of cutting gears around the circular material 3 to produce a resin gear.
However, in this technique, two reinforcing fiber bases 1 formed in a donut shape are used so as to overlap each other in the thickness direction of the metal bush 2, thereby sandwiching a protrusion provided on the outer periphery of the metal bush 2. The bush 2 is prevented from coming off, but the fiber entanglement is weak at the overlapping interface of the reinforcing fiber base, and the durability of the resin gear may be insufficient depending on the usage.

In order to solve these problems, Patent Document 2 describes a method of producing a reinforcing fiber base material by producing a short fiber aggregate by a papermaking method using short fibers. This is because the metal bush is placed in a cylindrical mold for paper making when the short fiber aggregate is made, and the protrusion provided on the outer periphery of the metal bush is placed in the short fiber aggregate. Buried.
According to this technique, the reinforcing fiber base made of the short fiber aggregate and the metal bush are integrated in advance, and thereafter, through a process of producing a circular material in the same manner as the technique disclosed in Patent Document 1. Resin gears are produced.
In addition, the resin gear often uses a helical gear as a gear form to improve the quietness, and the quietness is improved by improving the meshing rate.

JP 2001-295913 A JP 2009-250364 A

  However, when short fibers are accumulated by a papermaking method to produce a reinforcing fiber substrate, most of the short fibers are deposited in a direction in which the length direction of the short fibers intersects the direction in which the dispersion medium of the short fibers is discharged. For example, when discharged from the lower side of the papermaking apparatus, the length direction of the short fibers is randomly oriented in the horizontal direction (direction orthogonal to the discharge direction). Accordingly, the short fibers are accumulated while the radial direction thereof is stacked in the vertical direction (the discharge direction).

  For this reason, in the resin gear disclosed in Patent Document 2, as shown in FIG. 2, the fiber accumulation layer 4 in which short fibers are accumulated in a certain direction is present in the tooth portion. That is, FIG. 2 is a cross-sectional view of the resin gear in the rotational axis direction, and the horizontal straight line in the fiber accumulation layer 4 represents the length direction of the short fibers. Of course, the short fibers constituting the fiber accumulation layer 4 are present not only in the lateral direction but also in a random direction that is orthogonal to the rotational axis direction of the resin gear. Shows only the horizontal direction.

  In the conventional helical gear or spur gear, as shown in FIG. 3, the contact form of the tooth surface of the resin gear 5 and the tooth surface of the metal gear 6 is rolling contact, and the tooth surface of the metal gear 6 is Then, they abut against the tooth surfaces of the resin gear 5 and press each other. Therefore, the durable life of the resin gear was not affected by the fiber accumulation layer.

On the other hand, in the case of the worm wheel gear, as shown in FIG. 4, the contact form between the tooth surface of the resin worm wheel gear 7 and the tooth surface of the metal worm gear 8 is a sliding contact, and the tooth surface of the metal worm gear 8 is It slides on the tooth surface of the resin worm wheel gear 7.
At this time, when viewed microscopically, a state in which the tooth surface of the mating metal worm gear 8 abuts and a state in which the tooth surface of the mating metal worm gear 8 abuts appear at an arbitrary position on the tooth surface of the resin worm wheel gear 7. Further, microscopically, when teeth are formed by cutting on a resin worm wheel gear 7 using a reinforcing fiber base material produced by a papermaking method, FIG. As shown to A), the resin worm wheel gear tooth surface 9 has a convex part (for example, protrusion of a short fiber). When the metal worm gear tooth surface 10 comes into contact with the convex portion and moves in the direction of the arrow (left side in FIG. 5A), stress concentrates on the convex portion, and peeling occurs in the fiber accumulation layer 4. There is a problem that it becomes easy. Therefore, the durable life of the resin gear is easily affected by the fiber accumulation layer.

  The present invention provides a gear device that does not shorten the durable life of a resin gear even when a resin gear in which a cured resin is held on a fiber accumulation layer manufactured by a papermaking method is used as a worm wheel gear. Is intended to provide.

The present invention relates to the following.
(1) A gear device in which a resin gear in which a cured resin is held on a fiber accumulation layer produced by a papermaking method is used as a worm wheel gear and is combined with a worm gear. A worm gear having a tooth surface made of metal and a worm wheel gear having a tooth surface made of resin, the worm wheel gear having a resin gear portion disposed on an outer periphery thereof, the resin gear portion being A gear device in which a cured resin is held in a fiber accumulation layer in which short fibers are accumulated, and the layer direction of the fiber accumulation layer forms an angle of less than 90 degrees with respect to the advancing direction of the worm gear tooth surface. . Here, the layer direction of the fiber accumulation layer refers to the direction of the surface including the fiber length direction of most of the accumulated short fibers.

In the present invention, as shown in FIGS. 5B and 5C, the angle 11 formed by the layer direction of the fiber accumulation layer 4 with respect to the advancing direction of the metal worm gear tooth surface 10 is less than 90 degrees (acute angle). As a result, even if the resin worm wheel gear tooth surface 9 has a convex portion (for example, a short fiber protrusion), the metal worm gear tooth surface 10 is swept away, so that the occurrence of peeling of the fiber accumulation layer is suppressed. can do.
Therefore, in the gear device of the present invention, tooth surface wear can be reduced, and the durable life of the resin worm wheel gear can be improved.

The schematic perspective view of the resin gears which are a prior art example. The longitudinal cross-sectional view which shows the fiber integration layer of the resin gears shown in FIG. Explanatory drawing of the meshing direction of the tooth surface in a helical gear. Explanatory drawing of the meshing direction of the tooth surface in a worm wheel gear. Explanatory drawing of generation | occurrence | production of peeling of a fiber accumulation layer. The schematic diagram of preparation of a fiber accumulation layer. Schematic diagram of the molding die.

<Worm gear>
The worm gear described in the present invention is not limited to the other as long as at least the tooth surface in contact with the mating worm wheel gear is made of metal. Can be made of non-metal.
Although the tooth surface metal is not particularly limited, it is possible to use a hardened carbon steel, stainless steel, chromium molybdenum steel, a copper alloy casting, etc., and particularly using a hardened carbon steel is excellent in workability, It is preferable because a high level of tooth profile accuracy can be obtained.

<Worm wheel gear>
The worm wheel gear described in the present invention has a resin gear portion disposed on the outer periphery thereof, and a tooth surface is formed on the resin gear portion. From the viewpoint of strength and accuracy when the worm wheel gear is attached to the rotating shaft, it is preferable that a metal bush is disposed at the center of the worm wheel gear and a resin gear portion is provided around the metal bush.

Further, the resin gear portion is obtained by holding a cured resin in a fiber accumulation layer in which short fibers are accumulated, and the layer direction of the fiber accumulation layer is less than 90 degrees with respect to the advancing direction of the worm gear tooth surface. Make an angle.
The angle will be described in more detail. In the present invention, as shown in FIGS. 5B and 5C, with respect to the advance direction of the metal worm gear tooth surface 10 (left side in FIGS. 5B and 5C). The angle 11 formed by the layer direction of the fiber accumulation layer 4 of the resin gear portion needs to be less than 90 degrees. By doing in this way, even if there is a convex part formed by the fiber accumulation layer of the resin gear part, the worm gear tooth surface can be received and wear of the tooth surface can be minimized.
On the other hand, when the angle 11 is 90 degrees or more, as shown in FIG. 5A, the worm gear tooth surface moves so as to be caught by the convex portion formed by the fiber accumulation layer of the resin gear portion. Therefore, the wear of the tooth surface is increased and the life is shortened.

<Metal bushing>
The metal bush can be disposed at the center of the worm wheel gear, and is fixed to a rotating shaft that transmits transmission power from a drive source such as a motor for rotating the worm wheel gear.
The material of the metal is not particularly limited, but a sintered alloy, carbon steel, stainless steel, or the like can be used. In particular, it is preferable to use a sintered alloy in terms of the degree of freedom in shape and productivity.

<Resin gear part>
The resin gear portion described in the present invention is disposed on the outer periphery of the worm wheel gear described above, and can be produced by impregnating and curing a resin to a reinforcing fiber base produced by a papermaking method. .

The short fibers used in the papermaking method are not particularly limited, but natural fibers such as cotton and hemp, organic fibers such as aramid fibers (aromatic polyamide fibers) and polyamide fibers, carbon fibers, glass fibers and metals. Inorganic fibers such as fibers can be appropriately used depending on the intended use, and these short fibers may be used alone or in a plurality of types depending on the intended use. It is particularly preferable to use an aramid fiber because of its high strength, light weight, and high heat resistance.
Moreover, the dispersion medium at the time of papermaking is not particularly limited, but water is preferably used from the viewpoint of ease of post-treatment.
The slurry prepared by mixing the above short fibers and the dispersion medium is made into a paper, and a short fiber aggregate is produced. Then, the aggregate is compressed in the thickness direction to produce a reinforcing fiber base made of a fiber accumulation layer.

The resin to be impregnated and cured with respect to the reinforcing fiber base produced by the papermaking method is not particularly limited, but liquid resins such as polyaminoamide resin, epoxy resin, polyimide resin, phenol resin can be used, It is preferable to use a polyaminoamide resin from the viewpoints of manufacturability, heat resistance, strength and the like of the resin gear.
The layer structure of the resin gear portion is formed in a direction orthogonal to the direction in which the dispersion medium is discharged during papermaking, and is not necessarily formed by performing the papermaking process a plurality of times.

Further, the resin gear portion is a fiber assembly made of short fibers by heating and pressing a molding material prepared by a papermaking method from a slurry prepared by mixing short fibers, a powdered resin, and a dispersion medium to melt the resin. It can be produced by impregnating and curing the laminate.
As the short fibers used in the papermaking method, the same fibers as those of the reinforcing fiber base described above can be used, and these short fibers may be used alone or in plural types depending on the application. It is particularly preferable to use an aramid fiber because of its high strength, light weight, and high heat resistance.
Moreover, the dispersion medium at the time of papermaking is not particularly limited, but water is preferably used from the viewpoint of ease of post-treatment.

  Various materials such as a thermosetting resin and a thermoplastic resin can be used as the powdered resin used in the papermaking method (the powdery form includes a particulate form). For example, epoxy resin, polyaminoamide resin, phenol resin, unsaturated polyester resin, polyimide resin, polyethersulfone resin, polyetheretherketone resin, polyamideimide resin, polyamide resin, polyester resin, polyphenylene sulfide resin, polyethylene resin, polypropylene A combination of one or more resins selected from resins can be used. Among these, a phenol resin is preferable from the viewpoints of the strength and heat resistance of the cured resin.

The particle shape of the powdery resin is arbitrary, but a granular resin is preferably used. Moreover, although a particle diameter changes with fiber diameters of a short fiber, 50 micrometers or less are preferable. Thereby, the powdered resin can be uniformly distributed in the gaps between the short fibers of the short fiber aggregate.
A slurry prepared by mixing at least the above-described short fibers, powdered resin, and dispersion medium is made into a paper, and an aggregate of short fibers and powdered resin is produced. Then, the aggregate is compressed in the thickness direction to produce a molding material.

<Method 1 for producing worm wheel gear>
Although the worm wheel gear of the present invention is not particularly limited, for example, using a device having a function as shown in FIGS. 6 and 7, two steps of a reinforcing fiber base material manufacturing step and a resin gear manufacturing step Can be manufactured.

  First, regarding the reinforcing fiber substrate manufacturing process, the mass of necessary short fibers is measured to prepare the fibers. The fibers are put into a specified amount of water (dispersion medium) and the short fibers are stirred to prepare a slurry. Then, as shown in FIG. 6, in order to produce an aggregate of short fibers, the slurry prepared in a preforming mold in which the metal bush 2 is set in advance is poured, the short fibers are accumulated in the preforming mold, The integrated layer 12 is produced.

The preforming mold includes a cylindrical mold 13 for determining the outer diameter size of the reinforcing fiber base, bush support portions 14 and 15 for fixing the metal bush 2 inside the cylindrical mold 13, and integration. The apparatus has compression molds 16 and 17 for compressing the short fibers.
The compression mold 17 is provided with a through hole 18 for draining only the water of the slurry, and a mesh 19 for preventing the short fibers from coming out of the through hole 18 on the compression mold 17. Then, only the moisture is drained while collecting the short fibers on the mesh 19.

  After the short fibers are accumulated in the preforming mold, the accumulation layer is compressed by the compression molds 16 and 17 mounted on the preforming mold to perform dehydration and shape formation. Make it.

  Next, as a resin gear creation step, as shown in FIG. 7, the produced reinforcing fiber base material 20 is set in a molding die, the resin is impregnated into the reinforcing fiber base material, and heat pressure molding is performed. Create a circular material. This circular material is processed by cutting to form teeth, thereby producing a resin worm wheel gear.

<Method 2 for producing worm wheel gear>
Moreover, the worm wheel gear of the present invention can be manufactured in two processes, for example, a molding material manufacturing process and a resin gear manufacturing process, using an apparatus having functions as shown in FIGS.

  First, regarding the molding material manufacturing process, necessary short fibers and powdered resin are measured to prepare fibers and a resin. The fibers and the resin are put into a specified amount of water (dispersion medium), and the short fibers and the powdered resin are stirred to prepare a slurry. Then, as shown in FIG. 6, in order to produce an aggregate of short fibers and powdered resin, the prepared slurry is poured into a preforming mold in which a metal bush 2 is set in advance, and the short fibers and powdered resin are preliminarily prepared. An integrated layer 12 ′ is produced by integrating in a molding die.

The preforming mold includes a cylindrical mold 13 for determining the outer diameter of the molding material, bush support portions 14 and 15 for fixing the metal bush 2 inside the cylindrical mold 13, and an integrated short. The apparatus has compression molds 16 and 17 for compressing fibers and powdered resin.
The compression mold 17 is provided with a through hole 18 for draining the water of the slurry so that the short fibers and the powdered resin do not come out of the through hole 18 on the compression mold 17. The mesh 19 is placed, and moisture is drained while collecting the short fibers and the powdered resin on the mesh 19.

  After the short fibers and the powdery resin are accumulated in the preforming mold, the accumulation layer is compressed by the compression molds 16 and 17 mounted on the preforming mold to perform dehydration and shape formation, and the molding material 20 ′ is produced.

  Next, as shown in FIG. 7, as a resin gear production process, the produced molding material 20 ′ is set in a molding die, heated and pressed to melt the resin, and impregnated into a fiber accumulation layer composed of short fibers. Curing to make a circular material. This circular material is processed by cutting to form teeth, thereby producing a resin worm wheel gear.

  Embodiments of the present invention will be described below with reference to the drawings.

Example 1
In the present Example 1, as the reinforcing fiber base 20 constituting the resin gear portion, a material containing a meta-aramid fiber and a para-aramid fiber which are organic fibers is used.
The reinforcing fiber base 20 is composed of 50% by mass of meta-aramid fiber A (fiber length: 3 mm, fiber diameter: 10 μm), 45% by mass of para-aramid fiber B (fiber length: 3 mm, fiber diameter: 10 μm), para The system aramid fiber C (fiber length: 6 mm, fiber diameter: 10 μm) was mixed and used in an amount of 5 mass%.
The above-mentioned fiber is put in water and stirred to prepare a slurry. The amount of water was adjusted so that the slurry concentration at this time was 4 g / liter with respect to the fiber mass.

  Next, the metal bush 2 is set on the bush support portion 15 of the preforming mold shown in FIG. 6, and the previously prepared slurry is put into the preforming mold. The cylindrical mold 13 and the bush support portions 14 and 15 constituting the preforming mold constitute the outer diameter and inner diameter shape of the integrated layer. In this embodiment, the inner diameter portion of the cylindrical mold 13 is used. The diameter was 90 mm, and the outer diameters of the bush support portions 14 and 15 were 58 mm. Moreover, vacuum suction is performed from the lower side of the through-hole 18 to discharge moisture and separate fibers and moisture, thereby producing the integrated layer 12.

  After the integrated layer 12 is fabricated, the upper compression mold 16 is lowered in the axial direction of the metal bush 2 until the compression molds 16 and 17 heated to 150 ° C. have a distance of 18 mm. At this time, the bush support portions 14 and 15 move in conjunction with each other, and the center portion of the metal bush 2 is maintained at the center of the compression molds 16 and 17. The reinforcing fiber base 20 is produced by continuing the heating and pressurizing state for 2 minutes.

  Next, the produced reinforcing fiber substrate 20 is placed in a molding die 21 heated to 200 ° C. shown in FIG. 7A, and the molding die 21 is closed as shown in FIG. In order to reduce the internal pressure to 1.3 kPa or less, vacuum suction is performed for 5 minutes. After completion of the decompression, a resin in which 2,2 ′-(1,3-phenylene) bis-2-oxazoline: 69% by mass and 4,4′-diaminodiphenylmethane: 31% by mass was dissolved at a temperature of 140 ° C. and octyl was dissolved. Bromide: 1% by mass (external number) of agitated resin is injected into the mold, impregnated into the reinforcing fiber base 20, and heated and cured in the mold 21 for 3 minutes to obtain a circular material. . The circular material was cut using a hobbing machine so as to form teeth with an angle 11 shown in FIG. 5C of 45 degrees to obtain a resin worm wheel gear.

(Comparative Example 1)
The resin worm wheel gear obtained in Example 1 was used, and in the wear evaluation, the rotation direction was reversed from that in Example 1, and the evaluation was performed. At this time, the angle 11 shown in FIG. 5C is 135 degrees.

(Abrasion evaluation)
Using the resin worm wheel gear produced in Example 1, the tooth surface was evaluated for wear resistance. As a method, a resin worm wheel gear produced in a test machine was attached, a metal worm gear (material: hardened carbon steel, tooth surface polished product) was meshed, and evaluation conditions (rotation speed: 60 rpm, worm wheel load: 84. 8N · m), and the tooth surface wear and gear life were measured. Comparative Example 1 was evaluated by reversing the rotation direction from Example 1.
As a method for measuring the amount of wear in this evaluation, the backlash after a predetermined time elapsed from the start of the evaluation was measured, and the amount of change was compared with the backlash before the start of the evaluation.

(Gear durability life evaluation)
As a method for measuring the gear durability in this evaluation, a durability test was performed under the evaluation conditions described above, and the total number of revolutions when the resin worm wheel gear was damaged was defined as the gear durability life.

  Test results are obtained as shown in Table 1 and Table 2 below, and the angle formed by the advance direction of the metal worm gear tooth surface and the fiber accumulation layer of the resin gear portion is less than 90 degrees (acute angle). When 1 was set to 1, Comparative Example 1 resulted in an increase in tooth surface wear and a reduction in gear durability life. This is presumed to be caused by the fact that the fiber integrated layer is easily peeled off when the angle 11 is 90 degrees or more (obtuse angle).

  In the above-described first embodiment, the case where the reinforcing fiber base 20 according to the above-described worm wheel gear manufacturing method 1 is used has been described. In the case of using the molding material 20 ′ according to the worm wheel gear manufacturing method 2 described above, it is not necessary to inject the resin into the molding die 21 as in the first embodiment, and the molding material 20 ′ may be formed by heating and pressing. . Also in this case, the effect according to Example 1 was confirmed.

DESCRIPTION OF SYMBOLS 1 ... Reinforcement fiber base material, 2 ... Metal bush, 3 ... Circular material, 4 ... Fiber accumulation layer, 5 ... Resin gear, 6 ... Metal gear, 7 ... Resin worm wheel gear, 8 ... Metal worm gear, DESCRIPTION OF SYMBOLS 9 ... Resin worm wheel gear tooth surface, 10 ... Metal worm gear tooth surface, 11 ... Angle, 12, 12 '... Accumulation layer, 13 ... Cylindrical metal mold, 14, 15 ... Bush support part, 16, 17 ... Compression 18 ... through hole, 19 ... mesh, 20 ... reinforcing fiber substrate, 20 '... molding material, 21 ... molding die

Claims (1)

A gear device in which a resin gear in which a cured resin is held in a fiber accumulation layer produced by a papermaking method is used as a worm wheel gear, and this is combined with a worm gear,
A worm gear having a tooth surface made of metal and a worm wheel gear having a tooth surface made of resin, the worm wheel gear having a resin gear portion disposed on an outer periphery thereof, the resin gear portion being The cured resin is held in a fiber accumulation layer in which short fibers are accumulated, and the layer direction of this fiber accumulation layer (refers to the direction of the surface including the fiber length direction of most of the accumulated short fibers), A gear device that forms an angle of less than 90 degrees with respect to the advancing direction of the worm gear tooth surface.