JP4673271B2 - Dynamic damper and manufacturing method thereof - Google Patents

Description

  The present invention relates to a dynamic damper press-fitted into a rotating shaft of a motor and a method for manufacturing the same.

  For example, in a bracket-fixed type motor, a rotor is rotatably supported by a pair of brackets via a bearing with a rotation shaft. The rotary shaft is provided with a dynamic damper on the opposite side to the output side in order to prevent vibration, suppress or attenuate speed fluctuations, and reduce noise. The structure of this dynamic damper consists of a cylindrical hub that is press-fitted into a rotating shaft and an inertia disk that is provided on the outer side and that adds inertial mass to the rotor. The hub and inertia disk are rubber for vibration isolation. A material that is vulcanized and integrated with a material and integrated is used (see Patent Document 1).

The dynamic damper rotates idly when the pressure input to the rotating shaft is low, and if the pressure input is high, shaft runout or shaft breakage may occur. Therefore, the roundness and inner diameter tolerance of the hub may vary from several μm to several tens of micrometers. It must be within a tolerance of about μm. For this reason, as the hub, a cut product or a cast product obtained by cutting a metal material amount (iron alloy such as iron or brass) is used. When an iron-based sintered material is used, it is necessary to apply a rust preventive agent (for example, oil or adhesive) to the hub for rust prevention.
JP 2004-28295 A

When cutting is performed to determine the dimensions of the hub of the dynamic damper, the processing takes time and the workability is poor (particularly, the ferrous metal material has a poor cutability), resulting in an increase in manufacturing cost.
In addition, when iron-based metal materials are used, a rust preventive agent is applied after cutting, which increases man-hours, changes the inner diameter tolerance, and cannot ensure roundness. There is a risk of variation.
In recent years, in order to reduce the environmental load, there is a tendency that cadmium-containing materials are regulated, and there is a possibility that the use of brass parts containing cadmium is regulated. For this reason, when an expensive cadmium-free brass part is used as an alternative, the product cost increases.
Further, in the case of a machined product, the outer peripheral surface of the hub is formed in a smooth cylindrical shape, so it is difficult to expand the adhesion area with the rubber material.
Furthermore, if the hub is formed of a sintered material, the oil for bonding contained in the metal powder and the processing oil used in the processing process are likely to remain, and it is difficult to obtain an adhesive strength with the rubber material to be vulcanized. There is a problem.

  The present invention has been made to solve these problems. The object of the present invention is to provide a dynamic damper that can simplify the manufacturing process, facilitate dimensional accuracy, and is environmentally friendly at low cost. An object of the present invention is to provide a dynamic damper having improved adhesion strength between a binder and a vibration-proof member to be vulcanized.

In order to achieve the above object, the present invention comprises the following arrangement.
A dynamic damper that is press-fitted into the rotating shaft of a motor. An annular sintered material formed by heating and pressurizing metal powder with a press die is steamed to form an oxide film on the surface, and oil content by sizing a first annular member but which is removed by heating, and a second annular member for adding inertia mass provided concentrically without overlapping in the radial direction outer side, that is vulcanization bonded together by a rubber material It is characterized by that.
Further, the first annular member is characterized by using an iron-based or copper-based sintered material.
Also characterized in that vulcanization bonding surface between the rubber material of the first annular member and the second annular member is formed on the rough surface or uneven surface.

A method of manufacturing a dynamic damper that is press-fitted into a rotating shaft of a motor, wherein sizing is performed on a ring- shaped sintered material obtained by supplying metal powder to a press mold and heating and pressing, and further dimensioning is performed. A step of applying an adhesive to the outer periphery of the first annular member from which oil has been removed by heating and the vulcanized adhesion surface of the rubber material, which is the surface of the second annular member made of metal, and the first and second annular members It is characterized by including a vulcanization step of concentrically transporting the material into a mold and heating and pressurizing with the mold closed and vulcanizing and bonding to the rubber material .
The first annular member includes a first sintering step in which a metal powder as a raw material is heated and pressed in a mold to integrally form an annular sintered material, and the sintered material after sintering is subjected to a steam treatment. A rust prevention process that forms an oxide film on the surface to prevent rust, a sizing process that applies steam to the sintered material, and then carries the processing oil into the mold and measures the dimensions by pressure molding, and sizing It is characterized by being manufactured including a second sintering step in which the later sintered material is heated at a predetermined temperature to remove oil.
The second sintering step is characterized by heating the sintered material at a predetermined temperature of 260 ° C. or higher and 500 ° C. or lower that exceeds the boiling point of the processing oil used for sizing.

  If the above-described dynamic damper and the manufacturing method thereof are used, the first annular member integrally formed using a sintered material is used for the press-fitting portion to the rotating shaft. Dimensional accuracy such as roundness is easy to obtain, and the manufacturing process can be simplified and mass-produced at low cost. Further, even if an iron-based sintered material is used, a rust-preventing effect can be ensured without applying a rust-preventing agent to the final treatment because of the steam treatment. In addition, since it can be manufactured at low cost with a cadmium-free material, an environment-friendly product can be made. In addition, since it can be molded with a mold, the outer surface of the first annular member is made rough or uneven, and the adhesion area with the anti-vibration member is expanded without special processing of parts and products. Strength can be improved.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS A dynamic damper and a method for manufacturing the dynamic damper according to the invention will be described below with reference to the accompanying drawings. The dynamic damper is mainly pressed into the rotating shaft of the motor and used as a vibration isolating member. In the present embodiment, as an example of a motor, an inner rotor type stepping motor used for driving a scanner of a copying machine, driving a carriage of a printer, or feeding a paper will be described as an example.

A schematic configuration of the stepping motor will be described with reference to FIG.
In FIG. 1, the rotor is provided with a rotor core on which rotor teeth are formed, and rotates together with a rotating shaft 1 made of a nonmagnetic material. The stator is provided such that the rotor is surrounded by a stator core. The stator core is provided with a pole having stator small teeth opposed to the rotor small teeth provided on the rotor core, and a magnet wire is wound around the pole via an insulator. By switching the excitation phase to the magnet wire wound around the poles of the stator core and energizing, the rotor small teeth of the rotor core rotate to a position that is magnetically stable with the stator small teeth facing it. It is like that.

  The pair of brackets 2 and 3 pivotally support the rotor via bearings, and are fixed with screws by sandwiching the stator core on both sides in the axial direction. The rotary shaft 1 is provided so as to protrude outward through the mounting surface side bracket 2. For example, a gear or a pulley is fitted into the rotating shaft 1 protruding toward the motor mounting surface, and the motor is fixed to a mounting surface (not shown).

  The rotating shaft 1 is provided so as to protrude toward the rear bracket 3 side, and a dynamic damper 4 is press-fitted into the shaft end portion and assembled integrally. In FIG. 1, a dynamic damper 4 is made of a metal that adds a first annular member (hub) 5 integrally formed with a sintered material at a press-fitting portion to a rotary shaft 1 and an inertial mass provided outside the first annular member (hub) 5. A second annular member (inertia disk) 6 is vulcanized and bonded by a vibration isolating member (rubber material) 7 and assembled concentrically and integrally.

  When the motor is activated, the inertia disk 6 bonded to the rotating shaft 1 through the rubber material 7 together with the hub 5 also rotates. At this time, the rotation of the inertia disk 6 due to the inertial mass causes the rubber material 7 to be twisted in the direction opposite to the rotation direction, so that the vibration generated around the rotation shaft 1 can be attenuated. In the case of a stepping motor, vibration in a low speed range or a high speed range is likely to occur with intermittent driving, and therefore the dynamic damper 4 is preferably used.

The hub 5 is made of stainless steel or an iron-based sintered material (cadmium free), and is heated and pressed in a press die and integrally formed into a cylindrical shape. Hereinafter, an example of the manufacturing process of the hub 5 will be described.
The hub 5 is formed by integrally molding an annular sintered material by heating and pressing metal powder as a raw material with a press die (first sintering step). The sintering temperature varies depending on the metal powder material. For example, in the case of an iron-based sintered material (JIS standard; SMF430), heating is performed at 1100 ° C. or more and 1200 ° C. or less. Next, the sintered ring-shaped sintered material is subjected to a steam treatment, and an oxide film is forcibly formed on the surface to carry out a rust prevention process (rust prevention process).

  Next, at least before the steam treatment or after the steam treatment, the processing oil is applied to the sintered material, loaded into a mold, and pressed to perform dimensioning (sizing step). When the sizing process is performed before and after the steam treatment, rough molding is performed in the first sizing process, and detailed dimensions are determined in the second sizing process. The processing oil is mainly used to ensure the releasability between the sintered material and the mold. For this reason, since there is processing oil to be newly applied together with oil originally contained in the metal powder in the sintered material, it is necessary to degrease (wash) before vulcanization in order to improve the adhesion strength. There is.

  Therefore, the sizing material after sizing is heated at a predetermined temperature (for example, a temperature of approximately 260 ° C. or more and 500 ° C. or less) that is equal to or higher than the boiling point (eg, 260 ° C.) of the processing oil to remove oil (second sintering step). . In addition, when heated at a temperature of 500 ° C. or higher, the oxide film on the surface of the hub 5 subjected to the steam treatment may be peeled off and the rust prevention effect may be reduced. .

  The inertia disc 6 is a metal steel plate such as a hot rolled mild steel plate (SPHC). As the rubber material 7, a rubber material (NBR, NR, CR, IIR, silicone, EPDM, etc.) mainly considering vibration resistance and oil resistance is preferably used. The hub 5 and the inertia disk 6 are arranged concentrically on the mold surface, a rubber material is placed thereon, the mold is clamped and heated and pressed to vulcanize and bond the hub 5 and the inertia disk 6 to a dynamic damper. 4 is manufactured.

Here, a manufacturing method of the dynamic damper 4 using the hub 5 and the inertia disk 6 made of the sintered metal material described above will be described.
First, the hub 5 and the inertia disk 6 are degreased, and the vulcanized adhesion surfaces of the hub 5 and the inertia disk 6 from which oil has been degreased are each shot blasted to be roughened (roughening process). The roughening is performed on the outer periphery of the hub 5 and the surface of the inertia disk 6.

  After the surface is roughened, cleaning is performed once, and then an adhesive is applied to the outer periphery of the hub 5 and the surface of the inertia disk 6. That is, an adhesive is applied to the vulcanized adhesive surface with the vulcanized rubber (adhesive application step). Next, the hub 5 and the inertia disk 6 are carried concentrically into a mold (not shown), the rubber material is carried into the mold, and vulcanized and bonded by heating and pressing with the mold closed (vulcanization step). In addition, by making the outer peripheral surface of the hub 5 an uneven surface (rough surface), the adhesive area with the rubber material is increased, and the adhesive strength is improved. Thereby, the dynamic damper 4 in which the hub 5 and the inertia disk 6 are formed integrally with the vibration isolating member 7 is manufactured. The dynamic damper 4 is taken out from the mold and assembled by pressing the shaft hole of the hub 5 into the rotating shaft 1 of the motor.

According to the above-described dynamic damper and its manufacturing method, since it is integrally formed by pressing, there is little variation in dimensional accuracy such as inner diameter tolerance and roundness, and mass production is possible at a low manufacturing cost. Even if an iron-based sintered material is used, the rust prevention treatment is not necessary because the steam treatment is performed. Also. By roughening the surface (outer peripheral surface) of the hub 5 with the vibration isolating member 7 (roughening the surface), the bonding area can be expanded and the bonding strength can be increased.
For example, FIGS. 5 and 6 show an embodiment in which the adhesive surface is uneven. 5A to 5C show protrusions 8 provided on the adhesive surface (outer peripheral surface) of the hub 5 with the vibration isolator 7. 6A to 6C are diagrams in which both side surface portions 9 of the ridge 8 are involute-shaped and the bonding area is enlarged. By using such an uneven surface shape, the rotation prevention between the hub 5 and the vibration isolating member 7 can be strengthened. In addition, the uneven | corrugated surface shape provided in the outer peripheral surface of the hub 5 does not need to be provided over a perimeter, and may be provided in one place or at least 1 set may be provided in the position which opposes.

  In this embodiment, stepping motors (including PM type, VR type, and HB type) have been exemplified. However, the present invention is not limited to this, and can be widely applied to other motors such as brush motors and brushless motors. It is.

It is front explanatory drawing of a stepping motor. It is a rear view of a stepping motor. It is a top view of a dynamic damper. It is arrow AA sectional drawing of the dynamic damper of FIG. It is the top view of the hub which concerns on another example, a right view, and arrow EE sectional drawing. It is the top view of the hub which concerns on another example, a right view, and arrow FF sectional drawing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotating shaft 2, 3 Bracket 4 Dynamic damper 5 Hub 6 Inertia disk 7 Anti-vibration member 8 Projection 9 Side part

Claims (6)

A dynamic damper that is press-fitted into the rotating shaft of the motor,
An annular sintered material formed by heating and pressing a metal powder with a press die is steam-treated to form an oxide film on the surface, and a first annular member from which oil by sizing is removed by heating , and dynamic damper and the second annular member, characterized that you have been vulcanization bonded together by a rubber material for adding inertia mass provided concentrically without overlapping in the radial direction.   The dynamic damper according to claim 1, wherein the first annular member is made of an iron-based or copper-based sintered material. A first dynamic damper according to claim 1 or claim 2 wherein the vulcanization adhesive surface is formed on the rough surface or uneven surface between the rubber material of the annular member. A method of manufacturing a dynamic damper that is press-fitted into a rotating shaft of a motor,
Sizing the ring- shaped sintered material obtained by supplying metal powder to a press die and heating and pressurizing it, dimensioning it, and removing oil by heating and the outer circumference of the first ring member and metal Applying an adhesive to the vulcanized adhesive surface of the rubber material that is the surface of the second annular member;
A dynamic damper manufacturing method comprising a vulcanization step in which first and second annular members are carried concentrically into a mold and heated and pressurized with the mold closed and vulcanized and bonded to a rubber material . The first annular member is
A first sintering step in which a metal powder as a raw material is heated and pressed in a mold to integrally form an annular sintered material;
A rust-preventing step for steam-treating the sintered material after sintering to form an oxide film on the surface to prevent rust,
After the steam treatment , a sizing process in which processing oil is applied to the sintered material, carried into a mold and dimensioned by pressure molding,
The manufacturing method of the dynamic damper of Claim 4 manufactured including the 2nd sintering process of heating the sintered material after sizing at predetermined temperature, and removing an oil component. The method for producing a dynamic damper according to claim 5, wherein the second sintering step heats the sintered material at a predetermined temperature of 260 ° C. or more and 500 ° C. or less exceeding the boiling point of the processing oil used for sizing.

Images