JPS614883A - Method of manufacturing roots type fluid feeding cocoon shaped rotor - Google Patents

Abstract

PURPOSE:To accurately carry out resin coating of a Roots rotor by meshing a rotor shaped mold having projections with the same height as the thickness of a resin layer, on its periphery, with a Roots rotor similarly to a Roots blower, and rotating them while feeding a resin material to the meshed part. CONSTITUTION:On the peripheral surface 56 of a mold 54 having the same shape as a Roots rotor 40, plural projections 62 with the same height as the thickness of the layer of resin on the surface of the Roots rotor, are provided. The Roots rotor 40 to be resin treated is meshed with the mold 54 in a condition similar to a Roots blower, a powdered resin material 63 is fed to this meshed part from the flow out port 68 of a hopper 64 while heating the rotor, and the rotor and mold are rotated. As a result, a resin layer of a defined thickness is continuously formed on the surface of the Roots rotor.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a method of manufacturing a cocoon-shaped rotor used in a roots-type fluid feeder.

Prior Art One type of cocoon-shaped rotor used in Roots-type fluid feeders such as Roots-type blowers and Roots-type pumps has a resin layer on the outer peripheral surface of the rotor body.

According to this type of cocoon-shaped rotor, mutual interference between the rotors is absorbed by the resin layer on the surface, so that the mutual clearance between the rotors can be made as small as possible. The resin layer of such a cocoon-shaped rotor generally has a coefficient of thermal expansion five times larger than that of the rotor body, which is made of metal such as iron or aluminum. Therefore, in order to reduce thermal expansion changes in the external dimensions of the rotor, it is desirable to make the thickness of the resin layer as thin as possible within the range that maintains the above characteristics, for example, 0.3 to 0.5 fi. The resin constituting the resin layer has the ability to withstand temperatures of, for example, 100 to 120 degrees Celsius due to heat generated by adiabatic compression of gas in a roots-type turbocharger, heat generated by mechanical loss, etc. One of the reasons for this is that expensive materials with high heat resistance are used.

Problems to be Solved by the Invention However, in order to form a resin layer on the outer peripheral surface of the rotor body, resin layer forming methods such as the fluidized dipping method, electrostatic coating method, and resin sheet pressure bonding method have been attempted; However, mass production was poor, or sufficient precision could not be obtained in the resin layer formed. In other words, in the fluidized dipping method, a workpiece whose temperature has been raised to above the melting point of the resin is immersed in resin powder that has been brought into a fluidized state by an upward air current. Since only about .15m can be obtained, it is necessary to repeat re-heating and re-immersion.

In the end, if you try to obtain the desired thickness of the resin layer, the thickness will be 5 to 6.
There were several immersions, and it took, for example, 2 to 3 hours to produce one rotor. Furthermore, according to the electrostatic coating method, a film thickness of only about 0.1 nm can be obtained in one coating, and it takes much more time than the fluidized dipping method, resulting in extremely low productivity. The surface shape of the resin layer obtained by both of the above methods is extremely uneven, requiring finishing processing, and a large amount of resin is removed by finishing (this results in a reduction in the proportion of resin actually adhered to the outer peripheral surface of the rotor body). There was a drawback that it was not possible to obtain sufficient amounts.

On the other hand, in the method of wrapping a resin sheet of a constant thickness around the outer peripheral surface of the rotor body and bonding it by thermocompression, the desired film thickness can be obtained with just one wrapping, and the yield of resin is significantly improved. On the other hand, when pressing the resin sheet onto the outer circumferential surface of the rotor body using a pressure roller, it is inevitable that the surface pressure of the pressure roller differs between the concave portions and the convex portions of the rotor body outer circumferential surface, and due to this, There is a problem in that the thickness of the resin layer formed on the outer peripheral surface of the rotor body varies.

Means for Solving the Problems The present invention has been made against the background of the above circumstances.
The gist thereof is (11) a mold having an outer circumferential surface having the same shape as the cocoon-shaped rotor and a large number of protrusions protruding from the outer circumferential surface and having a height similar to the thickness of the resin layer; The rotor body is placed in a substantially horizontal plane with a phase relationship similar to that of a pair of cocoon-shaped rotors used in the roots-type fluid feeder, with the protrusion of the mold abutting the outer peripheral surface of the rotor body. a rotation process of rotating in opposite directions around mutually parallel axes located at (2);
) Prior to or at the same time as that step, a heating step of heating the rotor body, and (3) inserting a resin material between the mold and the rotor body, and applying the resin material to the outer peripheral surface of the rotor body. 1. A molding step of forming the resin layer by welding.

Operation and Effect of the Invention In this way, the projections protruding from the outer circumferential surface of the mold are brought into contact with the outer circumferential surface of the rotor body, thereby reducing the thickness of the resin layer between the mold and the rotor body. While a corresponding gap is formed, the resin material is sandwiched between the mold and the rotor body and both are rotated, so that the sandwiched resin material is compressed and welded to the outer peripheral surface of the rotor body. I am made to do so. Therefore, while the resin layer can be formed efficiently and with a high yield on the outer peripheral surface of the rotor body,
The thickness of the resin layer is precisely formed to a thickness corresponding to the height of the protrusion.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIGS. 1 and 2 are a front sectional view and a side sectional view of a roots-type supercharger 10 for a vehicle, which is a type of roots-type fluid feeder. In the figure, the cylindrical nose/Using body 12
An airtight pump chamber 18 is formed by closing the openings at both ends with end plates 14 and 16, respectively. A pair of cocoon-shaped rotors 20 and 22 are provided in the pump chamber 1B' so as to be rotatable around mutually parallel axes. The cocoon-shaped rotors 20 and 22 have rotating shafts 24 □ and 2 rotatably supported at both ends by the end plates 14 and 16 via roller bearings.
It is fixed at 6. A V-belt 2 is attached to one end of the rotating shaft 24.
A V-pulley 30 (not shown) provided on an engine or the like is fixed via a V pulley 30, and the rotational force transmitted via the pulley 30 is transmitted to timing gears fixed to the other ends of the rotating shafts 24 and 26, which mesh with each other. The signal is transmitted to the other rotating shaft 26 via 32 and 34. The timing gears 32 and 34 have the same number of teeth, and the cocoon-shaped rotors 20 and 22 are driven to rotate in opposite directions at the same speed. When the cocoon-shaped rotors 20 and 22 are rotated, for example, in the direction indicated by the arrow in FIG.
8 and is then pumped to the engine.

Since the cocoon-shaped rotors 20 and 22 are constructed in exactly the same way, the cocoon-shaped rotor 20 will be described below. As shown in FIG. 3, the cocoon-shaped rotor 20 is composed of a rotor body 40 made of iron or aluminum alloy and a fat layer 42 formed on the outer peripheral surface of the rotor body 40, and has a cocoon shape as a whole. There is.

The rotor body 40 is formed with a central hole 44 into which the rotating shaft 24 of the supercharger 10 is fitted, and a through hole 46 is formed in each of the pair of blades to reduce weight. The resin layer 42 is generally formed to have a thickness of about 0.3 to 0.5 mm, and is made of, for example, a resin which is a copolymer of tetrafluoroethylene and ethylene and has a trade name of "Aflon".

The cocoon-shaped rotor 20 configured as described above is manufactured through a resin layer forming process using the apparatus shown in FIGS. 4 and 5. In the figure, drive shafts 50 and 52 are drive shafts that are driven to rotate around mutually parallel axes in a substantially horizontal plane, and are driven to rotate at the same speed and in opposite directions. It has become.

That is, in FIG. 4, the drive shaft 50 is rotated clockwise and the drive shaft 52 is rotated counterclockwise. The rotor body 40 is removably fixed on the drive shaft 50, and the mold 54 is fixed on the drive shaft 52. The mold 54 has an outer peripheral surface 56 of similar dimensions to the cocoon-shaped rotor 20, at the ends of which a cocoon-shaped flange 58 and 60 are respectively secured. Further, a large number of protrusions 62 having a height corresponding to the thickness of the resin layer 42 of the cocoon-shaped rotor 20 are formed on the outer circumferential surface 56 .

The rotor body 40 and the mold 54 are a Roots type supercharger.
are fixed on drive shafts 50 and 52 with the same phase relationship as the cocoon-shaped rotors 20 and 22 in O,
The gap between the rotor body 40 and the mold 54 is accurately regulated by the projections 62 protruding from the outer circumferential surface 56 of the mold 54 coming into contact with the outer circumferential surface of the rotor body 40. Note that one of the drive shafts 50.52 may be supported so as to be able to move toward and away from the other, and the drive shafts 50.52 may be biased toward each other by biasing means such as a spring. good. In this way, the protrusion 62 on the outer circumferential surface 56 of the mold 54 can be reliably brought into contact with the outer circumferential surface of the rotor body 40 at all times.

A hopper device 64 is provided above the gap between the rotor body 40 and the mold 54 to supply powder or granular resin material 63 at a predetermined supply rate. The hopper device 64 is equipped with a shutter 66 for starting or stopping the supply of the resin material 63, and an outlet 68 through which the resin material 63 flows out when the shutter 66 is opened. 40 and the mold 54 as they rotate, and so that the outlet 68 is located as close as possible above the gap between the rotor body 40 and the mold 54 (not shown). The drive mechanism allows the rotor body 40 to move along a predetermined motion trajectory in synchronization with the rotation of the rotor body 40. Further, a heating device such as a heat transfer heater, an induction heating device, or an infrared heating device is disposed near or inside the rotor body 40 and the mold 54, so that the rotor body 40 should constitute the resin ff142. The temperature is lower than the decomposition temperature of the resin material 63 and higher than the molten salinity, for example 3
It is heated to about 20 to 340°C.

Further, the mold 54 is heated at a temperature approximately equal to the melting point of the resin, for example, 2.
It is heated to about 60°C.

Next, using the device configured as described above, the rotor body 4 is
The manufacturing process of forming the resin layer 42 on the outer circumferential surface of 0 will be explained.

First, the rotor body 40 is mounted on the drive shaft 50, and the drive shafts 50 and 52 are driven to rotate. Further, prior to or simultaneously with this, the rotor body 4° and the mold 54 are heated to a predetermined temperature by the aforementioned heating device. Thereafter, the shutter 66 of the hopper unit f164 is opened, and the powder or granular resin material 63 flows out from the outlet 68 between the rotor body 4o and the mold 54. At this time, due to the angle of repose (approximately 45 degrees) of the resin material 63, an appropriate amount of powder is formed above the gap between the rotor body 40 and the mold 54, and the resin material 63 is is filled evenly.

Since the rotor body 40 and the mold 54 are rotationally driven in the direction shown by the arrow in FIG. 4, the resin material 63 is sandwiched between the rotor body 40 and the mold 54 and compressed.
Since the rotor body 40 is heated above the melting point of the resin, the powder or granular resin material is melted to form a dense resin layer 42. Since the temperature of the mold 54 is approximately the melting point of the resin, this resin layer 42 is welded to the outer peripheral surface of the rotor body 40, which is heated to a high temperature that sufficiently melts the resin. Therefore, the resin layer 42 begins to be continuously formed as the rotor body 40 and the mold 54 rotate. FIG. 4 shows this state.

In this manner, the resin layer 42 is efficiently formed on the outer circumferential surface of the rotor body 40 with a high yield by rotating the rotor body 40 once, and its thickness is also formed with extremely high precision. That is, the rotor body 40
The gap between the outer circumferential surface of the mold 54 and the outer circumferential surface 56 of the mold 54 is always maintained accurately by the protrusions 62 protruding from the outer circumferential surface 56 of the rotor body 40. The thickness of the jit 42 is constant at all locations on the outer peripheral surface of the rotor body 40. Note that, as shown in FIG. 3, the formed resin layer 42
In this process, a large number of concave portions 70 are formed at positions corresponding to the protrusions 62, but these are extremely localized and do not communicate with each other, so the discharge efficiency of the Roots type supercharger 10 is affected. It has no effect.

As described above, according to this embodiment, the gap formed between the rotor main body 40 and the mold 54, which rotate in opposite directions, allows the protrusion 62 protruding from the outer circumferential surface 56 of the mold 54 to The thickness of the resin layer 42 formed on the outer circumferential surface of the rotor main body 40 is accurately formed regardless of the position in the circumferential direction because the resin layer 42 is formed accurately by contacting the outer circumferential surface of the rotor main body 40.

As a result, the cocoon-shaped rotor 20 after the resin layer 42 has been formed can be assembled into the housing with almost no finishing work required, and the yield of expensive resin materials is greatly improved. Furthermore, since the desired thickness of the resin layer 42 is formed while the rotor main body 40 is rotated once, the resin layer 42 is formed extremely efficiently. Therefore, the cocoon-shaped rotor 20 can be manufactured efficiently and at low cost.

In the above embodiment, the resin material 63 is in the form of powder or granules, but it may be preformed into a sheet.

The above-mentioned embodiment is merely one embodiment of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

[Brief explanation of the drawing]

1 and 2 are a front sectional view and a side sectional view showing a Roots type supercharger including a cocoon-shaped rotor, which is an application example of the present invention. FIG. 3 is a diagram illustrating the cocoon-shaped rotor of FIGS. 1 and 2. FIG. 4 and 5 are a front sectional view and a partial sectional view taken along the line 1--2 in FIG. 4, respectively, showing the apparatus used for manufacturing the cocoon-shaped rotor shown in FIG. 10: Roots type supercharger (Roots type fluid feeder) 40: Rotor body 42: Resin layer 54: Molding mold 56: Outer peripheral surface 62: Protrusion Applicant Toyota Motor Corporation Figure 1 Figure 2

Claims (2)

[Claims] (1) A method for manufacturing a cocoon-shaped rotor for a Roots-type fluid feeder, which includes a resin layer on the outer circumferential surface of a rotor body, which comprises: A mold having a large number of protrusions having a height similar to the thickness of the resin layer and the rotor body are connected to each other while the protrusions of the mold are brought into contact with the outer peripheral surface of the rotor body. a rotation step of rotating in opposite directions around mutually parallel axes located in a substantially horizontal plane with a phase relationship similar to that of a pair of cocoon-shaped rotors used in a feeder; and prior to or simultaneously with said step, said a heating step of heating the rotor body; and sandwiching a resin material between the mold and the rotor body;
A method for manufacturing a cocoon-shaped rotor for a roots-type fluid feeder, comprising a molding step of welding the resin material to the outer peripheral surface of the rotor body to form the resin layer. (2) The roots-type fluid according to claim 1, wherein the molding step involves inserting a resin material between the mold and the rotor body by pouring a powdered resin material. A method of manufacturing a cocoon-shaped rotor for a feeder.