JPH1110256A - Roll core bar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a roll core bar not loosening a fitted journal and high in pulling strength while keeping the easiness of production, low-cost, performance and light-weight performance even by using a low-rigidity material and even when applying strong torque or stress onto the roll core bar integrating a sleeve and a journal. SOLUTION: In this roll core bar, in which an inside guide 2 is provided at at least one end of a sleeve 1 and a journal 3 is inserted into the guide 2, the inside of the inside guide 2 is made to reversed taper of minus finish, an inserting part of the journal 3 is made to plus finish, and the journal 3 provided with a knurling 34 parallel to the inserting direction and an air vent 33 is fitted to the guide 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll mandrel in which a journal (shaft core) is fitted to a sleeve provided with a spigot at least at one end.
Cores such as pressure rolls or cores for rubber rolls with high rotational torque and pull-out strength, especially facsimile, electronic copy, office equipment such as word processors and personal computer printers or color printers, electronic equipment such as various measuring instruments and recorders Alternatively, the present invention relates to a roll core used for a roll of household electric appliances and the like.

[0002]

2. Description of the Related Art A roll core obtained by fitting a journal to a sleeve is inexpensive as compared with one manufactured by cutting from an integral round bar or the like by a cutting process, and is easy to manufacture, and the obtained roll core is obtained. Because of its advantages such as the lightness of gold, various sizes of roll cores have been used in a wide range of fields such as office equipment, electronic equipment, and household electrical appliances. However, since this kind of roll core is simply made by spigot processing on the sleeve and fitting the journal, after being assembled in those devices, strong torque or stress such as pressurizing operation is applied. However, the journal fitted into the sleeve is easy to loosen, and a problem such as that the journal loosens and comes off from the sleeve in a long-term use, or only the journal spins without being able to withstand a strong torque rotation. This problem frequently occurs in light metal materials which have been widely adopted in recent years for weight reduction as materials for these devices, particularly in materials having low rigidity as compared with materials such as carbon steel, such as aluminum or aluminum alloy. .

[0003]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a roll core made of a combination of a sleeve and a journal. The aim is to develop a roll core metal that does not lose its ease of manufacture, low cost, and lightness, does not loosen even under strong stress, withstands strong rotational torque, and has high pull-out strength. .

[0004]

According to the present invention, there is provided (1) an inlay provided on at least one end of a sleeve and a journal inserted into the sleeve, wherein the inside of the inlay is formed into a reverse-taper with a minus finish, and the journal is inserted. The roll core is fitted with a journal which has a knurled finish and air bleeding in parallel with the insertion direction. (2) When the knurl is assembled to the roll core, the entire knurl of the journal The journal was provided so that its end was slightly inserted into the inside from the spigot inlet, and the insert was chamfered (1).
(3) The roll core described in (1), in which the inside of the spigot and the insertion part of the journal are finished to a surface roughness of JIS standard 6S or less, and (4) Press-in allowance (diameter of journal -The diameter of the inlet entrance) is 10
The above object has been achieved by developing a roll core metal according to (1), which is 50 microns.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The material of the roll core of the present invention can be applied without any particular limitation, but in particular, problems such as falling off from the sleeve due to loosening of the insertion portion of the journal or idling of the journal tend to occur frequently. The present invention can be effectively applied to a roll core made of, for example, an aluminum alloy material such as a light metal having low rigidity or an engineering plastic.

Hereinafter, the present invention will be described in detail with reference to the drawings. As the sleeve 1, a pipe having a small thickness is used to reduce the weight as much as possible if the required strength can be maintained. The spigot 2 is provided at at least one end, usually at both ends thereof, and the insert portion 31 having the chamfered 32 of the journal 3 is inserted into the spigot 2 and fitted. The spigot 2 provided at at least one end of the sleeve 1 has a diameter slightly smaller than the insertion portion 31 of the journal 3 and has an inverse taper (a narrow spigot inlet, and a larger diameter at the middle).

[0007] The journal 3 has a chamfer 3 for guiding purpose at the tip of the insertion portion 31 so that it can be easily inserted into the sleeve.
2 is provided, and an air vent 33 is provided in order to release air that is obstructive at the time of fitting. Insertion part 31
Is slightly larger than the spigot 2, and the insertion is performed under pressure, so that the spigot 2 portion of the sleeve 1 is slightly deformed (the outer side is slightly thicker). Furthermore, knurling 33 is applied to the insertion portion 31 of the journal 3 to prevent the journal 3 from coming off,
Plays the role of preventing slip. The knurl is machined so that the peaks of the knurl 33 are positive with respect to the diameter of the journal 3, and the shape of the knurl 33 may be any shape that can be expected to have the effect of preventing slip-out and idling. Is a ridged knurl parallel to the direction in which the journal 3 is inserted. The journal has such a shape, and the knurl 33 is provided at a position where the entire portion of the knurl 33 is inserted into the spigot 2 when the journal 3 is inserted into the sleeve 1. By inserting in this manner, the unevenness of the knurl 33 bites into the inside of the spigot 2 of the sleeve 1, and has a great effect in preventing slipping of the journal 3 and prevention of detachment in combination with the reverse taper of the spigot.

The finishing (surface roughness) of the insert 31 of the spigot 2 and the journal 3 should be as precise as possible, preferably JIS standard 6S or less, more preferably JIS standard 3-4S. Also, since the taper of the spigot varies depending on the material, thickness, etc. of the sleeve 1 and the journal 3, it cannot be specified unconditionally.
The reverse taper is 0.01 to 0.02, the diameter of the insertion portion 33 of the journal 3 is inlay plus 10 to 50 microns, the bottom of the knurl 34 is almost flush with the cut surface, and the plus of the convex portion is 0. It is about 15 mm.

The roll cored bar having a practically usable rotational torque and pull-out strength has a press-fitting allowance (diameter of journal-diameter of spigot inlet) of 0-5.
0 microns, preferably 10 to 50 microns. By inserting a journal with such a large diameter into the spigot of the sleeve with a small inner diameter, the knurl does not bite into the inner surface of the spigot, and there is no looseness or idling even under a strong rotating torque. Biting into the inside of the spigot gives the journal a strong resistance to being pulled out. Assembling this roll core bar is easy by inserting a sleeve into the jig holder, avoiding center deviation, and press-fitting the journal with a journal press-fitting machine.
Can be assembled efficiently. The roll mandrel assembled in this manner has no eccentricity, and the rubber core or the like is wound around the sleeve or the outer periphery of the sleeve, vulcanized, and further coated with Teflon or the like to obtain a product.

[0010]

【Example】

(Example 1) As a sleeve, various sizes of spigots (inverted taper are unified to 0.01) were created in a pipe of material 6063TD and outer diameter of 14 mm, and a journal (material: 5056S, outer diameter of insertion portion: 11.150 mmφ) ,
Insert length 15mm, knurl height 0.2
mm and a knurling length of 2.5 mm) were inserted, and a test was performed for each of 20 points of pullout strength and rotational torque. The sleeve spigot has a press fit of 30 microns,
The test was performed at five levels of 16 microns, 5 microns, only the knurled portion, and similarly, only the knurled portion (there was a variation of about ± 3 microns). Table 1 shows the results. Withdrawal strength of 60 kg or more was secured as long as there was a press-fit allowance.

[0011]

[Table 1] ^{1) The} rotation torque is 124 kg on average, but there are some that move with a pull-out strength of 60 kg, which has a problem in strength. ^{2) The} rotational torque was low and the pullout strength exceeded the 60kg line.

[0012]

The roll mandrel assembled in this manner has a minus finish of the inlay and a reverse taper.
It is an excellent roll core that is firmly connected to the journal and that is reliably prevented from slipping due to the knurls and spigots of the journal penetrating into the inner surface, and is not loosened or dislodged by the influence of stress or the like.

[Brief description of the drawings]

FIG. 1 is a perspective view of a sleeve and a journal used for a roll core of the present invention.

[Explanation of symbols]

Reference Signs List 1 sleeve 2 spigot 3 journal 31 insertion part 32 chamfer 33 air release 34 knurl part

Claims (4)

[Claims] 1. A sleeve in which a spigot is provided at at least one end, and a journal is inserted into the spigot, and the inside of the spigot is reverse-tapered with a minus finish, the insert portion of the journal is plus-finished, and further parallel to the inserting direction. A roll core, wherein a journal provided with air bleeding is fitted together with knurling. 2. The knurling position is such that when assembled on a roll core, the entire knurl of the journal is inserted, the end of which is slightly inserted into the inside of the spigot inlet, and the insertion portion is provided. 2. The roll core according to claim 1, wherein the journal is a chamfered journal. 3. The roll core according to claim 1, wherein the inside of the spigot and the insertion portion of the journal are finished to a surface roughness of JIS standard 6S or less. 4. The roll core according to claim 1, wherein the press-fitting allowance (diameter of journal—diameter of spigot inlet) is 10 to 50 microns.