JPS60104865A - Compound gear - Google Patents

Abstract

PURPOSE:To reduce a manufacturing cost, by fixing a metallic gear of small contour to be inserted into a boss part, when a gear of large contour and its boss part made of resin material are formed by molding. CONSTITUTION:A boss part 1 and spur gear part 2 of large contour are integrally molded by a thermo-plastic resin material of ''Durcon'' or the like using a molding metal mold. A pinion 3 of small contour, after it is previsouly molded by a metallic material, is secured by molding when a compound gear is integrally formed by molding. Here an axial hole of the pinion 3 is secured to an intermediate part of small thickness in the boss part 1 consisting of resin material. The compound gear obtained in such way has an advantage providing sufficient molding strength and gear teeth row strength further eliminating any necessity for lubricating a bearing part.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite gear used in a gear tray of precision instruments and the like.

For example, in the gear trains of precision instruments, two-stage gears are often used, which consist of a large-diameter gear and a small-diameter pinion mounted on both ends of a common boss. Metal two-stage gears are difficult to process, which increases the cost of the parts, and after assembly, the bearings require lubrication to lubricate them. In addition, in conventional two-stage gears made of resin, it is difficult to provide sufficient strength to the teeth of the small-diameter binion, which is subject to large load stress, and there is a problem that deterioration and wear of the tooth arrangement easily occur. Ta.

The present invention has been made to solve the above-mentioned problems, and the purpose of the present invention is to have low manufacturing cost and sufficient molding strength and tooth strength [7]. The object of the present invention is to provide a composite gear that does not require lubrication.

To achieve this object, the composite gear of the present invention is a composite gear in which a large diameter gear and a small diameter gear are integrally formed coaxially, and the large diameter gear is formed of a resin material. The small diameter gear is made of a metal material, and the diameter of the large diameter gear and the small diameter gear is 11ξ1j+3?
The gear part is formed integrally with the large diameter gear.
'j It is said that the fact that the form F is also formed by A is a positive sign.

The present invention will be explained by referring to an embodiment shown in the drawings.

The composite gear of the embodiment is as shown in Figures 1 to 4, the boss part 1 and the large-diameter spur gear part 2 are made of thermoplastic material such as Souracon using a molding die to be described later. The small-diameter binio/3, which is integrally molded for convenience, is molded in advance from a metal material and then fixed with a mold during the integral molding.

Therefore, the pinion 3 is formed by the meat γ71i 3a and the communicating southern part 3b, and the shaft hole of the pinion 3 is fixed to the thin-walled part in the middle of the boss l made of the resin material. There is.

In addition, in the illustrated state where the binion 3 is fixed by mold,
The tooth portion 3b and the tooth portion 3a forming the spur gear 2 side half of the binion 3 are embedded in the boss portion 1, and the tooth portion 31)
A protruding portion 3C integral with the resin material of the boss portion 1 is injected into the side end of the part row space from the boss portion 1, and a collar 1a is further provided at the end of the boss portion 1 next to the pinion 3. The pinion 3 is prevented from being removed by the collar 1a.

By the way, when molding the composite gear of the embodiment configured as described above, as shown in FIG. 5, an upper mold 4 and a lower mold 5 are used. In this case, a pin-shaped inner die 6 for drilling the shaft hole of the gear is inserted from below, and a ready-made metal pinion 3 is fitted into the upper part 5a of the center hole. .

The resin material poured into the mold from the upper pouring lower passes through the passage 4a of the upper mold 40 and enters the mold space between the two molds 4 and 5, where it is molded into a composite gear. Ru.

Note that during this molding, the resin material that flows into the teeth 31) of the binion 3 and forms the protrusion 3c is cooled and solidified by the metal material of the binion 3, so that the molten resin does not flow between the teeth of the binion 3. This has the advantage of preventing the occurrence of flakes due to leakage from the mold.

In the lumbering gear of the example manufactured in this way, since the pinion 3 is made of metal, there is less risk of damage, wear, deterioration, etc. of the small diameter gear, and the pinion 3 is made of metal. By injecting the resin into the space of the tooth arrangement, it is firmly fixed to the boss part l, and there is no risk of rotation slippage, and further,
Since it is clamped by the lever 3a, there is no risk of it slipping off, and in this way, the 1-binion 3 is reliably integrated into the boss portion 1.

In addition, the above-mentioned molding method is easy and simple to process, so the cost per part is low.

In the configuration of the embodiment described above, a groove 1a was formed at the end of the boss l to prevent the pinion 3 from being pulled out, but instead of this, a groove 1a was formed as in the embodiment shown in FIG. In addition, the above-mentioned flange on the end face of the boss portion 1 is omitted, and the pinion 3 is omitted.
Similar effects can be obtained by forming a groove 3d on the outer peripheral wall or inner peripheral wall near the spur gear 2, and forming a resin material into the groove 3d.

As described above, according to the composite gear according to the present invention, the large-diameter gear and the gear boss are integrally formed by molding a resin moon, and at the time of the molding process, the boss has a metal small-diameter Since the gears are inserted into a composite structure of double-layer gears, an inexpensive composite gear with sufficient molding strength and tooth row strength can be obtained, and the bearing part does not require lubrication, making the use of gears easier. This has the effect of improving performance, reliability, and economy.

[Brief explanation of drawings]

FIG. 1 is a side view of a composite gear showing an embodiment of the present invention;
Figure 2 is a front view of the same, Figure 3 is a diametrical view of the same, Figure 4 is a
FIG. 5 is a cross-sectional schematic diagram of a mold used for molding the composite gear of the embodiment, and FIG. 6 is a side sectional view of the composite gear showing another embodiment of the present invention. 1...Boss part, 1a...Brim, 2...Spur gear as a large diameter hour wheel, 3...Pinion as a small diameter gear. Patent applicant Satoshi Nishimura, patent attorney representing Chino Seisakusho Co., Ltd. First box Figure 1 Figure 3 Figure 5 Figure 7 Figure 6

Claims (4)

[Claims] (1) In a composite gear in which a large-diameter gear and a small-diameter gear are coaxially formed, the front aL large-diameter gear is formed of a resin material, and the -1: small-diameter gear is formed of metal scrap. In addition, the large diameter gear and the front 7; [: bearing boss portion of the small diameter gear are formed of a resin material integrally formed with the large diameter gear. (2) The small-diameter pawl has a tooth row space close to the large-diameter gear at the peak thereof, which is formed by a protrusion formed from a resin phase integral with the large-diameter gear. 2. An interlocking gear as claimed in claim 1, characterized in that it is comprised of: j'f'F; (3) The boss portion has a small diameter end. The composite gear according to claim 1, wherein the composite gear is formed into a large-diameter flange-shaped boxwood with a "2" protruding from the end face of the small-diameter gear. (4) The small diameter gear has a peripheral wall near the large diameter gear,
The composite gear according to claim 1, wherein the ring groove filled with the resin material is formed by recess molding.