JPH07119754A - Rotation transmitting shaft fixing structure for braking drum - Google Patents

Abstract

PURPOSE:To provide the rotation transmitting shaft fixing structure for a braking drum which can be fixedly processed with ease, and can also be lowered in cost exceedingly. CONSTITUTION:In a braking drum can, the insertion section 7 of a rotation transmitting shaft 5 is inserted into the shaft locking hole 4 of the base plate section 3 of a braking drum 1. The braking drum 1 is locked in the direction of a drum cylinder center by the support surface 8a of a projected section 8, and the tip end of the insertion section 7 of the rotation transmitting shaft 5 is in a state that it is projected out of the shaft locking hole 4. In this place, the braking drum 1 can be squeezed so as to be fixed between a plastically deformed squeezing section 7a, the supporting surface 8a and the shaft locking hole 4 only by squeezing the projected tip end of the insertion section 7 with a squeezing rod 11. Therefore, the braking drum 1 and the rotation transmitting shaft 5, which are separately fabricated in advance, can be simply fixed. Beside, they can be fixedly processed at room temperatures, there is thereby no need for post treatment after they have been fixed. As a result, it can be materialized that the rotation transmitting shaft fixing structure for the braking drum is lowered in cost exceedingly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is inserted into a braking drum such as a clutch drum or a brake drum used in a relatively small prime mover such as a brush cutter or an agricultural machine, and a shaft locking hole of the braking drum. The present invention relates to a rotation transmission shaft fixing structure for a braking drum that fixes the rotation transmission shaft.

[0002]

2. Description of the Related Art Generally, a component in which a braking drum and a rotation transmitting shaft for transmitting power between the braking drum and the braking drum are integrated is called a "braking drum canbi".
Incidentally, as described above, with respect to the braking drum cambi used in a relatively small prime mover, it is general that a relatively large coupling strength is not required between the braking drum and the rotation transmission shaft. As a method of manufacturing such a braking drum cambi, an integrated manufacturing method in which raw materials to finished products are integrally manufactured from the beginning to the end, and a separately manufactured braking drum and a rotation transmission shaft are fixed in a later process. It is roughly divided into individual manufacturing methods for finished products.

Examples of the former integrated manufacturing method include a grinding manufacturing method in which a finished product is obtained by cutting out from a round bar-shaped steel material, and a forging manufacturing method in which a finished product is obtained by performing a forging step of integral molding a plurality of times. The braking drum cambi manufactured by these integral manufacturing methods has an advantage that it has a relatively large strength with respect to the coupling state between the braking drum and the rotation transmission shaft. On the other hand, in the above-described grinding method, it is necessary to perform the centering and accurate grinding of the braking drum and the rotation transmitting shaft at the same time. Further, in the forging manufacturing method described later, for example, when it is necessary to form a heat dissipation hole or the like in the braking drum, it is necessary to newly perform the drilling process of the heat dissipation hole or the like in the finished product obtained with high centering accuracy. However, there was a possibility that the accuracy of the heart was lost.

On the other hand, FIG. 7 shows a conventional braking drum cambi obtained by the latter individual manufacturing method. In the figure, 1a
Is a braking drum which is manufactured by pressing from a thick sheet metal material and has a substantially U-shaped side cross section. The braking drum (not shown) is in sliding contact with the inner peripheral surface of the peripheral drum portion 2, and the drum cylinder core portion. It is composed of a substrate portion 3a in which a circular shaft locking hole 4a is formed when viewed in the drum core direction. This braking drum 1
At the same time when the a is manufactured, a heat dissipation hole or the like (not shown) can be punched and formed in the substrate portion 3a.

Reference numeral 5a is a rotation transmission shaft for transmitting a rotational force to and from the braking drum 1a, and an insertion portion 7b at one end of the shaft body 6 is fitted in a shaft locking hole 4a of the braking drum 1a. It is made possible. A projecting portion 8 protruding outward in the radial direction is formed over the entire circumference of the shaft body 6 near the insertion portion 7b, and the braking drum 1a is supported by the support surface 8a on the insertion portion 7b side in the drum cylinder center direction. It is designed to be locked to.
Therefore, the braking drum 1a and the rotation transmitting shaft 5a are held in a coaxially centered state, and are brazed together using, for example, copper or the like so as to be integrally fixed to each other, whereby a braking drum can be completed.

[0006]

As described above, according to the conventional individual manufacturing method of the braking drum cambi utilizing the brazing, attention is paid only to the machining precision required for each of the braking drum 1a and the rotation transmitting shaft 5a. However, there is a case where the braking drum 1a and the rotation transmission shaft 5a are relatively eccentric to each other due to deformation due to heat during brazing. Generally, since the inner peripheral surface of the peripheral plate portion 2 of the braking drum 1a is required to have a relatively high roundness, the braking drum 1a of the eccentric braking drum can and the like are subjected to post-processing. Shaping is required. For this reason, there is a problem that the manufacturing cost is rather increased because it is troublesome.

The present invention has been made in view of the conventional problems, and an object of the present invention is to provide a rotation transmission shaft fixing structure for a braking drum, which can be easily fixed and the processing cost is extremely low. Is.

[0008]

In order to achieve the above object, a rotation transmission shaft fixing structure for a braking drum according to the present invention comprises:
A braking drum having a rotation transmission shaft formed with a protrusion projecting outward in the radial direction near one end, and a shaft locking hole through which one end of the rotation transmission shaft can be inserted, formed in the drum cylinder. And a structure in which the length from the protrusion of the rotation transmission shaft to the tip of the one end is projected from the shaft locking hole, and the tip of the one end protruding from the shaft locking hole is crushed. The braking drum is fixed at least between the protrusion and the protrusion.

Further, the brake drum and the rotation transmitting shaft may be provided with a rotation stopping mechanism for fixing the rotation transmitting shaft in a direction around the drum cylinder center.

[0010]

In the structure for fixing the rotation transmission shaft of the braking drum according to the present invention, first, one end of the rotation transmission shaft is inserted from the tip thereof into the shaft locking hole of the braking drum. At this time, the braking drum is locked in the direction of the drum cylinder center by the protrusion of the rotation transmission shaft, and the tip of one end of the rotation transmission shaft is made to project from the shaft locking hole of the braking drum. Therefore, only by crushing the tip of the one end of the rotation transmitting shaft protruding from the shaft locking hole, the braking drum is pinched and fixed between at least the tip of the crushed one end and the protrusion.

Further, in the case of adopting the structure provided with the anti-rotation mechanism for fixing the braking drum and the rotation transmitting shaft in the direction around the drum cylinder center, the braking drum and the rotation transmitting shaft are arranged in the direction around the drum cylinder center. The fixed state is secured.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a front view showing a braking drum used in a braking drum cambi according to an embodiment of the present invention, FIG. 2 is a side sectional view of the braking drum of FIG. 1, and FIG.
Shows a rotation transmission shaft used in the braking drum cambi of this embodiment. FIG. 4A is a side view including a partial cross section, FIG. 4B is a front view, and FIG. 6 is a front view showing a state in which a rotation transmission shaft is caulked and fixed to a side cross section, FIG. 5 is a front view showing a caulking-fixed braking drum cam, and FIG. 6 is a rear view showing another example of the braking drum.
In these figures, the same reference numerals are used for the elements common to the conventional braking drum cambi shown in FIG. 7, and the detailed description thereof will be omitted. In addition, the components having the same functions as those of the conventional braking drum canbi have the same numerical symbols and the symbols without the subscripts are used.

As shown in FIGS. 1 and 2, the braking drum 1 used in the braking drum cambi according to the present embodiment is shown in FIG.
The basic structure is substantially the same as that of the conventional braking drum 1a shown in FIG. 2, and the difference in the configuration from the conventional braking drum 1a is that the polygonal shape in the drum cylinder center portion of the substrate portion 3 when viewed in the drum cylinder center direction Here, for example, an octagonal shaft locking hole 4 is formed.

Further, as shown in FIGS. 3 (a) and 3 (b), the rotation transmission shaft 5 used in this braking drum cambi has a basic structure with the conventional rotation transmission shaft 5a shown in FIG. The configuration is substantially the same as that of the conventional rotation transmission shaft 5a, except that the insertion portion 7 from the projection 8 to the tip of the shaft body 6 on one end side penetrates the base portion 3 of the braking drum 1 by a length L. And that the shape of the insertion portion 7 when viewed in the drum cylinder center direction is formed in an octagonal shape that can be fitted into the shaft locking hole 4.

The braking drum 1 and the rotation transmission shaft 5 of this embodiment.
Are configured as described above. Subsequently, the fixing operation of the braking drum 1 and the rotation transmission shaft 5 will be described with reference to FIGS.
Will be described below with reference to. First, the insertion portion 7 of the rotation transmission shaft 5 is fitted into the shaft locking hole 4 from the back side of the braking drum 1 and inserted, and the tip of the insertion part 7 is projected from the front side of the shaft locking hole 4 to form the base plate portion 3 The peripheral portion of the shaft locking hole 4 of the support surface 8a of the projection 8
Support in. Further, the shaft center of the rotation transmitting shaft 5 and the braking drum 1
Each of them is relatively positioned (centered) and held so as to be coaxial with the drum cylinder center. These operations are performed by previously supporting the shaft holding jig 9 (indicated by a chain double-dashed line in FIG. 4) that previously supports the shaft body 6 and the support surface 8b of the rotation transmitting shaft 5, and the peripheral plate portion 2 of the braking drum 1 in advance. Drum holding jig 10
(Indicated by a chain double-dashed line in FIG. 4) and are executed.

With the braking drum 1 and the rotation transmitting shaft 5 held as described above, the tip of the insertion portion 7 protruding from the front side of the shaft locking hole 4 is crushed by a crush rod 11 (two-dot chain line in FIG. 4). By smashing (in the direction of arrow B of the chain double-dashed line), the tip of the insertion part 7 is plastically deformed in the radial direction and the crushed part
a. Here, the crushed portion 7a has a substantially circular shape in a front view as shown in FIG. In the figure, reference numeral 12 is a recessed portion formed corresponding to the octagonal side portion of the insertion portion 7 by the crushing operation. In this way, the substrate portion 3 of the braking drum 1 is caulked and fixed between the crushed portion 7a and the support surface 8a of the protrusion 8.

In this case, since the opening shape of the shaft locking hole 4 and the front shape of the insertion portion 7 are relatively matched, the crushed portion 7a also presses the inner peripheral surface of the shaft locking hole 4. . Therefore, the braking drum 1 is reliably positioned and fixed also in the radial direction. However, the opening shape of the shaft locking hole 4 and the front shape of the insertion portion 7 do not necessarily need to be substantially matched to each other so that they can be fitted to each other. Even if a gap is formed between them, the caulking fixing is performed. Sometimes, the braking drum 1 is crushed by the collapsing portion 7a and the protruding portion 8
It suffices that the structure is such that it is securely fixed in the drum cylinder center direction with respect to the supporting surface 8a.

As described above, according to this embodiment, the braking drum 1 and the rotation transmitting shaft 5 which are manufactured separately are crushed at room temperature at the tip of the insertion portion 7 protruding from the shaft locking hole 4. By a simple operation such as caulking and fixing, an integrated braking drum can can be manufactured. Further, unlike the conventional example, eccentricity between the braking drum 1 and the rotation transmission shaft 5 does not occur due to deformation due to high heat. Therefore, it is not necessary to reshape the braking drum or the like when it is eccentric as in the conventional example. As a result, the braking drum cambi of this embodiment has the advantages that it is less laborious and the manufacturing cost is extremely cheaper than the conventional example.

Further, since the shape of the insertion portion 7 of the present embodiment viewed in the direction of the drum cylinder center is a polygonal shape which can be fitted into the opening shape of the shaft locking hole 4, the braking can be performed. The drum 1 and the rotation transmission shaft 5 are securely locked and fixed in the direction around the drum cylinder center. That is, the structure including the shaft locking hole 4 formed in a polygonal (here, for example, octagonal) opening shape and the insertion portion 7 of the rotation transmission shaft 5 fitted and locked in the shaft locking hole 4 is the main structure. It is an example of the rotation stopping mechanism of the invention.

As another example of the anti-rotation mechanism of the present invention, the shape of the shaft locking hole and the insertion portion that can be fitted into the shaft locking hole is
For example, it may be oval.

On the other hand, instead of the braking drum 1, a braking drum 1b as shown in FIG. 6 can be used. The braking drum 1b has a knurled groove portion 13 formed by knurling at the peripheral portion of the shaft locking hole 4a of the conventional braking drum 1a. When the braking drum 1b is caulked and fixed to the rotation transmission shaft 5a, the knurled groove portion 13 is pushed into the support surface 8a of the protrusion 8 to ensure that the braking drum 1b and the rotation transmission shaft 5a are rotated around the drum cylinder center. Fix it.
That is, a configuration in which the knurled groove portion 13 provided in the peripheral portion of the shaft locking hole 4a of the base plate portion 3a and the support surface 8a of the protrusion 8 are engaged is another example of the rotation preventing mechanism of the present invention.
Incidentally, such a knurled groove portion may be provided on the surface of the peripheral edge portion of the shaft locking hole 4a on the side in contact with the crushed portion 7a.

[0022]

Since the structure for fixing the rotation transmission shaft of the braking drum according to the present invention is configured as described above, the tip of one end of the rotation transmission shaft that is inserted and protrudes from the shaft locking hole of the braking drum. The braking drum and the rotation transmitting shaft, which are separately manufactured in advance, can be easily fixed only by crushing the. Moreover,
No post-treatment step after fixing is required. Therefore, it is possible to realize the rotation transmission shaft fixing structure for the braking drum described above at an extremely low processing cost.

Further, when the brake drum and the rotation transmitting shaft are provided with the rotation stopping mechanism for fixing the rotation transmitting shaft in the direction around the drum cylinder center, the braking drum and the rotation transmitting shaft are securely arranged in the direction around the drum cylinder center. Can be fixed to.

[Brief description of drawings]

FIG. 1 is a front view showing a braking drum used in a braking drum cambi according to an embodiment of the present invention.

FIG. 2 is a side sectional view of the braking drum of FIG.

3A and 3B show a rotation transmission shaft used in a braking drum cambi of this embodiment, FIG. 3A is a side view including a partial cross section, and FIG. 3B is a front view.

FIG. 4 is a side sectional view showing a state in which a braking drum and a rotation transmission shaft are fixed by crimping.

FIG. 5 is a front view showing a braking drum can, which is fixed by crimping.

FIG. 6 is a rear view showing another example of the braking drum.

FIG. 7 is a side sectional view showing a fixed state of a conventional braking drum cambi, which is an example of the background of the present invention.

[Explanation of symbols]

 1, 1b Braking drum 3, 3a Base plate part 4, 4a Shaft locking hole 5, 5a Rotation transmission shaft 7 Insertion part 7a Crushing part 8 Projection part 8a Support surface 13 Knurled groove part

Claims (2)

[Claims] 1. A rotation transmission shaft having a protrusion projecting outward in the radial direction near one end, and a shaft locking hole through which one end of the rotation transmission shaft can be inserted are formed in a drum cylinder core. The structure for fixing to the braking drum is configured such that the length from the protrusion of the rotation transmission shaft to the tip of the one end is formed to project from the shaft locking hole, and A rotation transmission shaft fixing structure for a braking drum, characterized in that a tip of the braking drum is crushed to fix the braking drum between at least the protrusion. 2. The rotation transmission shaft fixing structure for a braking drum according to claim 1, further comprising a rotation stopping mechanism for fixing the braking drum and the rotation transmission shaft in a direction around the drum cylinder center.