JPH05187447A - Connecting structure of shaft body - Google Patents

Abstract

PURPOSE:To provide a connecting structure of a shaft which can obtain satisfactory connecting strength and is excellent in dimensional accuracy and shaft accuracy. CONSTITUTION:In a connecting structure of a shaft body for connecting a shaft body 24 such as a rotary shaft or the like to the end surface of a driving unit 20 such as a platen or the like in a printing apparatus, a taper engaging hole 22 expanded toward the end surface is formed on the end surface of the driving unit 20, and the connected end portion of the shaft body 24 is formed to be tapered extending over a designated length. Further, plural peripheral grooves 26 and projecting peripheral portions 28 between the peripheral grooves 26 are formed on the taper portion. The taper portion is pressed in the taper engaging hole 22 of the end surface of the driving unit 20, and the outer end sides of the projecting peripheral portions 28 are deformed toward the opening end of the engaging hole 22 not to fill up the interior of the peripheral groove 26, so that the shaft body 24 is connected to the end surface of the driving unit, with the outer end side of the projecting peripheral portion 28 strongly biting into the inner wall of the engaging hole 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft portion connection structure.

[0002]

2. Description of the Related Art It is necessary to connect a rotary shaft to an end surface of a rotating body (driving body) such as a platen in a printing apparatus. When connecting the rotary shafts, it is required that the connection strength be capable of withstanding a torque of a predetermined value or more. In addition, in a rotary shaft such as a platen, an accessory member such as a drive gear is attached at a predetermined position on the rotary shaft, and thus a predetermined dimensional accuracy may be required. Conventionally, in order to connect a shaft body portion such as a rotary shaft to the drive body, a plurality of knurls 12 extending in the axial direction are formed on the outer periphery of the tip end portion of the shaft body portion 10 as shown in FIG. , A fitting hole 16 provided in the driving body 14
It is common to press fit into and fix. Alternatively, a method of welding and fixing the tip end surface of the shaft body portion 10 to the end surface of the driving body 14 is used.

[0003]

However, in the method of engraving and press-fitting the knurl, the projection of the knurl is crushed and the knurl cannot be press-fitted to a predetermined depth or more, and the shaft 10 is not pressed.
However, there is a problem that the dimensional accuracy is not good and that the crushed fragments are exposed to the end face of the driving body 14 through the groove of the knurl. Further, when the welding method is used, it is difficult to accurately extract the axis of the shaft body portion 10, and there is a possibility that problems such as shaft runout may occur.

Therefore, the present invention has been made to solve the above problems, and an object of the present invention is to provide a connecting structure of a shaft body which can obtain sufficient connection strength and is excellent in dimensional accuracy and shaft accuracy. To provide.

[0005]

The present invention has the following constitution in order to achieve the above object. That is, in the connecting structure of the shaft body portion that connects the shaft body portion such as the rotating shaft to the drive body end surface such as the platen in the printing device, the drive body end surface is formed with the tapered fitting hole that widens toward the end surface, The end portion of the body portion to be connected is formed into a taper portion that is tapered over a predetermined length, and a plurality of peripheral grooves and a protruding peripheral portion between the peripheral grooves are formed in the taper portion, The tapered portion is press-fitted into the tapered fitting hole on the end face of the driving body, and the outer peripheral side of the projecting peripheral portion is deformed toward the opening end direction of the mating hole to such an extent that it does not fill the circumferential groove, It is characterized in that the shaft body portion is connected in a state where the end side strongly digs into the inner wall of the fitting hole.
It is preferable that the protruding peripheral portion is formed as a corner protruding peripheral portion having an outer peripheral portion having a predetermined width. Further, the protruding portion may be formed as a continuous thread.

[0006]

According to the connecting structure of the shaft portion according to the present invention, as described above, the tapered fitting hole is provided in the end surface of the driving body, and the end portion of the shaft portion is also formed in the tapered portion, and the tapered portion is formed. Since a plurality of protruding parts are formed on the
The press fitting causes the protruding part to fall toward the opening end of the fitting hole, and even if you do not press the tapered part of the shaft part deeply into the tapered fitting hole, if you press it to a certain depth or more, the connection strength above the specified level will be obtained. As a result, a range can be obtained, and therefore, there is a margin in the press-fitting dimension of the shaft portion, and it is possible to easily press-fit while ensuring dimensional accuracy within the above range and to secure a connection strength of a predetermined level or more.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a first embodiment. Two
Reference numeral 0 is a platen (driving body), and tapered fitting holes 22 are formed in both end surfaces thereof. The diameter of the tapered fitting hole 22 is expanded toward the opening side, and the taper angle is about 1 °.
A very moderate taper is preferred. Reference numeral 24 denotes a rotary shaft (shaft portion), and the end portion of the tapered fitting hole 22 to be press-fitted is formed into a taper taper over a predetermined length. The circumferential groove 26 and a plurality of angular projecting portions 28 between the circumferential grooves are formed. The depth and the like of the circumferential groove 26 are determined by the thickness and the like of the rotary shaft 24, but in the embodiment, the diameter of the rotary shaft 24 was set to 8 mm and the depth of the circumferential groove 26 was set to 1 mm. The width of the circumferential groove 26 is not particularly limited. The width of the protruding portion 28 is set to 0.5 mm in the above embodiment. The taper angle of the tapered portion of the rotary shaft 24 is also set to about 1 °. In addition,
The taper angle of the fitting hole 22 and the taper angle of the taper portion of the rotary shaft 24 do not necessarily have to match, but they need to be close to each other.

The tapered portion of the rotary shaft 24 is press fitted into the tapered fitting hole 22 of the platen 20. Then, the protruding portion 28 of the tapered portion is strongly pressed against the inner wall of the fitting hole 22, and is deformed so as to fall toward the opening end direction of the fitting hole 22 as shown in FIG. The rotating shaft 24 is fixed in a state in which the outer end side strongly digs into the inner wall of the fitting hole 22. What is important in this case is that the circumferential portion 26 is not completely laid down and the depth of the circumferential groove 26 is fixed so that the rotary shaft 24 is fixed in a state where the circumferential groove 26 is not completely filled and there is a gap. That is, that is, the height of the protruding portion 28 is set. That is, the rotating shaft 24 is in a state in which it can be pushed in if it is still pushed in, and is in a fixed state at a stage in the middle of press-fitting. Even if the tapered portion of the rotary shaft 24 is not completely and deeply press-fitted into the fitting hole 22, there is a range in which a predetermined or more connection strength can be obtained by press-fitting the taper portion over a certain depth. In the embodiment of the above size, the range can be ensured over 2 mm or more. Therefore, there is a margin in the press-fitting size of the rotary shaft 24, and it is possible to easily press-fit while maintaining the dimensional accuracy within the above range and to secure a connection strength of a predetermined level or more. Chips and the like when the rotary shaft 24 is press-fitted into the peripheral groove 2
6 is held in the platen 6, is exposed on the end surface of the platen 20, and is not dropped.

FIG. 3 shows a protruding peripheral portion 28 and a peripheral groove 26 of the rotary shaft 24.
An example in which a taper portion is formed in a continuous screw shape is shown. Also in this embodiment, by setting the taper angle, the height of the protruding portion 28 and the like to a predetermined value, it is possible to secure a certain press-fitting dimension capable of obtaining a connection strength of a predetermined value or more, and a bonding strength of a predetermined value or more. Moreover, the rotary shaft 24 can be press-fitted with high dimensional accuracy.

The cross-sectional shapes of the projecting peripheral portion 28 and the peripheral groove 26 are not limited to those described above, and the abacus ball shape as shown in FIG. 4, the sawtooth shape as shown in FIG. 5, the knuckle shape with the rounded edges in FIG. 6, etc. It is possible to make the shape.

Various embodiments of the present invention have been described above. However, the present invention is not limited to this embodiment. For example, the driving body and the shaft portion are not limited to metal, but synthetic resin or the like. Of course, many modifications can be made without departing from the spirit of the invention.

[0012]

According to the connecting structure of the shaft portion of the present invention, as described above, the tapered fitting hole is formed in the end surface of the driving body, and the end portion of the shaft portion is also formed in the tapered portion.
Since a plurality of projecting peripheral portions are formed in the tapered portion and press-fitted, the projecting peripheral portions fall down toward the fitting hole opening end due to the press-fitting, and the tapered portion of the shaft portion is not completely fitted in the tapered fitting hole. Even if you do not press it deeply, if you press it to a certain depth or more, there will be a range where a connection strength of more than a predetermined value will be obtained, so there will be a margin in the press-fitting dimension of the shaft part, and press-fitting while maintaining dimensional accuracy within the above range, Moreover, it has become possible to easily secure a connection strength higher than a predetermined level.

[Brief description of drawings]

FIG. 1 is an assembly diagram showing a first embodiment.

FIG. 2 is an explanatory diagram showing a connection state of a protruding peripheral portion.

FIG. 3 shows an embodiment in which a protruding peripheral portion is formed in a screw shape.

FIG. 4 shows an embodiment in which a projecting portion is formed in an abacus ball shape.

FIG. 5 shows an embodiment in which the protruding portion is formed in a sawtooth shape.

FIG. 6 shows an embodiment in which a protruding portion is formed in a knuckle shape.

FIG. 7 is an explanatory diagram of a conventional connecting structure of a shaft portion.

[Explanation of symbols]

 20 Platen (Drive Body) 22 Tapered Fitting Hole 24 Rotating Shaft (Shaft Body) 26 Circumferential Groove 28 Protruding Circumferential Portion

Claims (3)

[Claims] 1. In a connecting structure of a shaft body portion for connecting a shaft body portion such as a rotary shaft to an end face surface of a drive body such as a platen in a printing device, a tapered fitting hole is formed in the end surface of the drive body to expand toward the end surface. The end portion of the shaft portion to be connected is formed into a taper portion which is tapered over a predetermined length, and a plurality of peripheral grooves and a protruding peripheral portion between the peripheral grooves are formed in the taper portion. The tapered portion is press-fitted into the tapered fitting hole on the end face of the driving body,
The outer peripheral side of the projecting part faces toward the opening end of the tapered fitting hole,
A connecting structure for a shaft body part, wherein the shaft body part is connected in a state where the shaft body part is deformed to such an extent that it does not fill up the circumferential groove and the outer peripheral side of the projecting peripheral part strongly digs into the inner wall of the tapered fitting hole. 2. The connecting structure for a shaft portion according to claim 1, wherein the protruding peripheral portion is formed as a corner protruding peripheral portion having an outer peripheral portion having a predetermined width. 3. The connecting structure for a shaft portion according to claim 1, wherein the protruding portion is a continuous thread.