JP2004197768A - Resin molding type torque transmission member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin molding type torque limiter or a hinge maintaining bidirectional stable torque value, not susceptible to receiving torque fluctuation caused by service environment or a resin shape in molding, and molded irrespective of shapes of parts. <P>SOLUTION: In a resin molding type torque transmission member, a metal sleeve 1 in which a rotating shaft 2 is press-fit is included in a synthetic resin material 3. When torque is applied to the rotating shaft 2, the synthetic resin material 3 maintains mechanical strength in a degree of preventing an opening part of the metal sleeve 1 from opening, so as to suppress influence of toque fluctuation affected by the service environment of the torque limiter or a molding shape of resin. A hole 4 for fixing a position in molding is formed in an area surrounded by the rising parts 1a, 1b of the opening part and an outer face of the rotating shaft 2 to prevent displacement of the metal sleeve 1 from the synthetic resin material 3 in molding. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque limiter for preventing an overload on a drive motor of various robots, or a hinge suitable for holding a lid having a relatively large torque at an arbitrary opening and closing angle. About.
[0002]
2. Description of the Related Art In general, a robot or a relatively complicated automatic machine uses a plurality of stepping motors or servomotors. In order to protect these motors from overload, a force exceeding a set torque is applied. In such a case, a torque limiter may be provided that acts so as to start rotating and prevent a larger force from being applied to the motor. In particular, a torque limiter or hinge for such an application is required to have a small size, a long-term stable and relatively large rotational torque.
A conventional resin-molding type torque transmitting member is a metal shaft member that rotates integrally with a lid member of a personal computer or the like, and a shaft rotation support member made of a synthetic resin material that rotatably supports the metal shaft member. And utilizes the torque between the metal shaft member and the synthetic resin shaft rotation support member. (For example, see Patent Document 1).
In addition, a metal sleeve having a metal sleeve having an open portion in part is made up of a metal sleeve covered with a synthetic resin and a rotating shaft press-fitted into the metal sleeve, and rotational torque due to frictional resistance of internal stress caused by shrinkage during molding of the synthetic resin. There is also one that uses the following (for example, see Patent Document 2).
[0003]
[Patent Document 1]
JP-A-2000-27846 (Section 3-4, FIG. 1)
[Patent Document 2]
Japanese Patent Application No. 2001-141296 (Section 4-6, Fig. 1-2)
[0004]
However, such a resin type torque limiter uses a metal material as a rotating shaft member and a synthetic resin molded so as to include a part of the metal material. There has been a problem that torque fluctuations occur due to thermal shrinkage of the synthetic resin due to the environment, and the torque becomes unstable particularly when there are many occupied portions of the synthetic resin.
Also, when injection molding the outside of the rotating shaft press-fitted into the metal sleeve with synthetic resin, slits are provided on the insert side to perform positioning during molding, but depending on the shape of the rotating shaft, mold matching may occur during molding. In other words, there was a case where the slit position could not be fixed because the mold interference occurred, which caused molding failure.
An object of the present invention is to solve such a problem, and to reduce the influence of torque fluctuations due to the use environment and the molding shape of the resin, and to obtain a resin-type torque transmission capable of obtaining a stable bidirectional torque value. It is intended to provide a member.
Further, it is characterized in that mold interference during injection molding is prevented, alignment can be performed regardless of the shape of the rotating shaft, and synthetic resin can be easily molded.
[0006]
Means for Solving the Problems Claim 1 of the present invention, in order to solve the above problems,
A torque transmission member utilizing friction resistance between a metal sleeve and a rotating shaft press-fitted into the metal sleeve,
The metal sleeve has an open portion partially open in the longitudinal direction, and has an upright portion at which both ends of the open portion are raised, and at least one portion of the synthetic resin material filled in the groove of the open portion. And a resin-molding-type torque transmitting member characterized in that holes are provided in the resin molding die.
According to a second aspect of the present invention, there is provided a torque transmitting member utilizing frictional resistance between a metal sleeve and a rotary shaft press-fitted into the metal sleeve.
A resin-molding torque transmitting member, characterized in that a hole is provided in at least one place of the synthetic resin material filled in the groove of the open portion,
An object of the present invention is to provide a resin-molding type torque transmitting member in which the synthetic resin material surrounds the circumferential direction of the metal sleeve so as not to hinder the torque fluctuation due to the heat shrinkage of the synthetic resin material.
According to a third aspect of the present invention, there is provided a resin-molding-type torque transmitting member according to the second aspect, wherein a lightening portion is provided in at least one portion of the synthetic resin material.
[0009]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a resin mold torque limiter according to the present invention will be described with reference to FIGS. The resin mold torque limiter 1 includes a metal sleeve 1 made of a metal material tempered for a spring and having a relatively large wall pressure, a rotating shaft 2 press-fitted into the sleeve 1, and an upright portion 1a of the metal sleeve 1. And synthetic resin material 3 formed so as to cover 1b. The rotating shaft 2 may rotate itself or may rotate in conjunction with the rotation of the metal sleeve 1. Reference numeral 4 denotes a hole for fixing a position during resin molding. Here, the hole is desirably a through hole, but may be a hole closed on one side or a hole partitioned at the center. The metal sleeve 1 has open portions that are opened at narrow intervals and rising portions 1a and 1b that rise from both ends of the open portion, and the height thereof is longer than the thickness of the metal sleeve 1. The width of the open portion, that is, the interval between the rising portions 1a and 1b is, for example, about a fraction of the diameter of the rotating shaft 2, and this interval becomes wider than the first due to the press fitting of the rotating shaft 2. Therefore, the metal sleeve 1 can effectively function as a spring by the opening.
In the synthetic resin existing in a region surrounded by the upright portions 1a and 1b of the open portion and the outer surface of the rotary shaft 2, holes 4 for fixing the position during injection molding of the synthetic resin are formed. . The holes 4 are traces of pulling out the positioning pins on the receiving mold at the time of injection molding. The positioning at the time of molding can be easily performed, and when the metal sleeve 1 and the rotary shaft 2 press-fitted into the metal sleeve 1 are molded. To prevent mold interference.
Although the shape of the position fixing hole 4 is arbitrary, it is assumed that the position fixing hole 4 is located inside or near the upright portions 1a and 1b.
In a region between the position fixing hole 4 and the outer surface of the rotating shaft 2, a material made of an oil-containing material 5 containing a lubricant such as grease as necessary is provided except for both ends. . Although it is difficult to maintain the lubrication performance for a long period of time even if the lubricant is applied to the inner surface of the metal sleeve 1 or the outer surface of the rotating shaft 2 in advance, in a state where the oil-impregnated material 5 is provided in the open portion, FIG. As shown in the drawing, a crystalline resin such as polyacetal, or a synthetic resin material 3 obtained by adding various types of reinforcing fibers to the resin is injection-molded so as to cover the tip surfaces of the rising portions 1a and 1b. At this time, it is preferable that both ends of the upright portions 1a and 1b of the metal sleeve are invisible, that is, the open portion of the metal sleeve 1 is covered with the synthetic resin material 3. Accordingly, the oil-containing material 5 is confined, so that the lubricant does not flow out and contaminate the rotating shaft 2 and its surroundings, and the lubrication performance is maintained for a long period of time.
According to this structure, since only the upright portions 1a and 1b of the metal sleeve 1 are formed so as to be covered with the resin, when the rotating force is applied to the rotating shaft 2, the rotating force of the rotating shaft 2 is increased. This causes a force to open the raised portions 1a and 1b of the metal sleeve 1, but the opened portion cannot be opened because the filled resin presses the raised portions 1a and 1b from the outside, so that the torque is reduced. A large two-way rotational torque can be obtained without the need. That is, the synthetic resin material 3 has a mechanical strength higher than that of preventing the opening from opening when a rotational force is applied. Further, since the opening portion is provided with the hole 4, the function of the spring is further enhanced. That is, as compared with the case where the resin is filled in the open portion, the presence of the holes 4 increases the force for pressing the upright portions 1a and 1b from the outside, and has an effect of making the open portion more difficult to open.
Providing the holes 4 in the open portion has the effect of reducing the occupied portion of the filling resin and suppressing torque fluctuation due to thermal shrinkage of the filling resin.
If the mechanical strength described above is obtained, the heat shrinkage ratio between the raised portions 1a and 1b of the metal sleeve 1 made of a metal material and the synthetic resin material 3 is small, and the torque fluctuation is not hindered, As shown in FIGS. 3 and 4, the synthetic resin material 3 may be formed so as to surround the entire circumference of the metal sleeve 1, or as shown in FIGS. . Here, the lightening portion 6 is desirably a through hole, but may be a closed hole or a hole partitioned at the center, and the shape is not limited to a concave portion. As a result, the thermal shrinkage of the synthetic resin material 3 due to a change in the use environment can be kept low, the fluctuation range of the torque becomes small, and a stable torque can be obtained.
Since the oil-impregnated material 5 between the upright portions 1a and 1b of the metal sleeve 1 and the rotating shaft 2 is confined by the molding resin, it is possible to maintain the lubrication performance for a long time and maintain a stable torque limit value. A torque limiter that can be provided. However, this is not necessary.
In each of the above embodiments, a torque limiter has been described. However, the same applies to a torque transmission member such as a hinge used between a lid and a main body of various mechanical devices, electronic equipment, pianos and the like. Can be implemented.
[0014]
As described above, according to the present invention, a torque limiter or a resin mold for a resin molding die which is hardly subject to torque fluctuations due to the use environment and the resin shape at the time of molding and can obtain a stable bidirectional torque value. A hinge can be provided.
[Brief description of the drawings]
FIG. 1 shows an external appearance example of a resin mold torque limiter according to the present invention.
FIG. 2 shows a sectional view of a resin mold torque limiter according to the present invention.
FIG. 3 shows an example of the appearance of a resin mold torque limiter according to the present invention.
FIG. 4 shows a sectional view of a resin mold torque limiter according to the present invention.
FIG. 5 shows an example of the appearance of a resin mold torque limiter according to the present invention.
FIG. 6 shows a sectional view of a resin mold torque limiter according to the present invention.
1-metal sleeve 1a, 1b-standing portion of metal sleeve 2-rotation shaft 3-synthetic resin material 4-hole for molding positioning 5-oil-containing material 6-lightening portion

Claims (3)

In a torque transmission member utilizing frictional resistance between a metal sleeve and a rotating shaft press-fitted into the metal sleeve,
The metal sleeve has an open portion partially open in the longitudinal direction, and has an upright portion at which both ends of the open portion are raised, and is formed by molding a synthetic resin material so as to cover at least the upright portion. ,
A resin-molding torque transmitting member, wherein a hole is provided in at least one portion of the synthetic resin material filled in the groove of the opening. In a torque transmission member utilizing frictional resistance between a metal sleeve and a rotating shaft press-fitted into the metal sleeve,
A resin-molding torque transmitting member, characterized in that a hole is provided in at least one place of the synthetic resin material filled in the groove of the open portion,
A resin-molded torque transmitting member in which the synthetic resin material surrounds the metal sleeve in a circumferential direction to such an extent that torque fluctuation due to thermal shrinkage of the synthetic resin material is not hindered. 3. The torque transmitting member according to claim 2, wherein a lightening portion is provided in at least one portion of the synthetic resin material.

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