JPH05240218A - Key - Google Patents

Abstract

PURPOSE:To provide a pin type key with high jointing force by displacing a semi-circular block of half-divided structure which is fitted on a tapered pin in a radial direction at the time of screwing a nut or the like onto a threaded part formed at one end on its smaller diameter side, and towing the tapered pin in an axial direction. CONSTITUTION:This key, which is installed on an interface or the like between a drive shaft and a driven shaft fitted thereto, is fitted in a circular keyway formed by overlapping semi-circular grooves formed in respective shafts, and consists of a pair of blocks 5, a tapered pin 3, and a tightening means 6 such as a nut. The tapered pin 3 of circular section has an outer periphery formed into a tapered shape, and threaded part 2 at the end of its smaller diameter side. A pair of blocks 5 are provided with a tapered recessed part 4 of roughly semi-circular section which roughly-matches the tapered surface of the tapered pin 3 at a long and narrow side surface of semi-circular section. The respective blocks 5 are designed so that they may be displaced outwards at the time of screwing the nut 6 on the threaded part 2 and towing the tapered pin 3 in an axial direction to bring them into pressure contact with the keyways in the respective shafts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pin-shaped key for connecting a drive shaft and a driven shaft, and more particularly, when the key is mounted, the key can be reliably placed in the key groove without impacting the bearing. Regarding what can be fixed.

[0002]

2. Description of the Related Art Tapered pins are often used as pin-shaped keys for connecting a drive shaft and a driven shaft. That is, one of the drive shaft and the driven shaft is fitted into the other,
A circular hole is formed in the boundary portion, and a taper pin is hit and fitted into the circular hole. If the taper pin is hit in this manner, the bearing may be damaged especially in the servomotor of a precision machine, so that the key must be driven carefully and with skill.

[0003]

Therefore, there is a demand for a key that can be easily installed by anyone without damaging the bearing of such a precision machine, and has a simple structure and excellent mass productivity. Was there.

[0004]

Therefore, the present invention has the following constitution in order to solve the above problems. That is, the key of the present invention has a tapered pin 3 having a circular cross section and an outer periphery formed on the tapered surface 1, and a screw portion 2 is provided on the outer periphery of one end portion in the longitudinal direction thereof. At the same time, it has a pair of elongated blocks 5, each of which is formed with a tapered concave portion 4 that matches the tapered surface 1 on one side surface thereof, and has the same semicircular outer peripheral cross section. The fastening means 6 is screwed onto the threaded portion 2 of the taper pin 3, and the relative rotation of the fastening means 6 causes the taper pin 3 to move relative to the blocks 5 and 5 in the axial direction. Furthermore, a pair of the blocks 5, 5
When the two taper recesses 4 and 4 are overlapped so as to face each other, the inner circumferences of their axial cross sections are slightly deformed from the perfect circles, whereby the taper recesses 4 are tapered in the overlapped state. When 3 is inserted, taper pin 3
It is characterized in that a part of the outer peripheral surface of is first contacted with the central portion in the circumferential direction of the tapered concave portion 4 of the blocks 5, 5.

[0005]

As shown in FIGS. 1 and 2, a pair of blocks 5 face each other in opposite directions, a taper pin 3 is arranged between them, and they are combined to form a semicircular shape between a drive shaft 7 and a driven shaft 8. Insert into the key groove so that the overlapping surfaces of both blocks are located at the center of the key groove as shown in FIG. Then, both sides of the taper pin 3 are in contact with only the central portion of the semicircle of each block 5 by about 10% of the circle, for example, and about 90% of the non-contact portion 13 is formed near the side wall surface 12 of each block. In FIG. 3, the small gap 9 between the block 5 and the keyway is, for example,
It is about 0.01 to 0.03 mm. Therefore, the fastening means 6 is screwed onto the screw portion 2 and rotated to move the taper pin 3 relative to the blocks 5 and 5. Then, as shown in FIG. 4, the gap between the block 5 and the key groove disappears, and the small gap 9 is formed between the side faces of the pair of blocks 5 and 5 by that much.

In such a state, the non-contact portion 13 is about 10% as an example, and the contact surface between the taper pin 3 and the taper recess is about 90%. When the gap between the block 5 and the key groove is too large, the entire inner peripheral surface of the tapered recess of the block 5 is pressed against the taper pin 3 as shown in FIG. or,
The key can be removed by loosening the fastening means 6.

[0007]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a perspective view showing each component of the key of the present invention, and FIG. 2 is a side view showing its assembled state, and FIG.
[Fig. 4] is a cross-sectional view showing a usage state of the key of the present invention, which is a state before the fastening means 6 is fastened. 4 to 6 each show the state in which the fastening means 6 is fastened. The key for this example is
It has a pair of elongated blocks 5, taper pins 3 and fastening means 6. The taper pin 3 has a circular cross section and a tapered outer circumference, and the threaded portion 2 is formed at one end of the taper on the small diameter side. At the same time, a wrench hole 10 is formed on one end surface thereof. Instead of the wrench hole 10, a notch 11 into which the tip of a flat-blade screwdriver is fitted may be formed as shown in FIG.

Next, each of the pair of blocks 5 is formed with a tapered recess 4 having a semicircular cross section on one side surface of an elongated bar having a semicircular cross section. The tapered recess 4 is aligned with the tapered surface of the tapered pin 3. The outer diameter of the screw portion 2 of the taper pin 3 is smaller than the minimum radius of the taper surface 1. As a result, as shown in FIG. 2, when the taper pin 3 is sandwiched between the pair of blocks 5, the tip of the taper recess 4 is prevented from coming into contact with the screw portion 2. The pair of blocks 5 and the taper pin 3 may be manufactured by cutting, or may be manufactured by casting, rolling, press molding or the like. In the case of cutting, the pair of blocks 5 can be manufactured as follows. That is, a pair of blocks each having a semicircular outer peripheral section and a semicircular concave portion having the same minimum radius as the tapered concave portion is prepared. These blocks can be easily manufactured by conventional techniques such as drawing.

The semi-circular flat surface of such a block is polished. Then, the polished flat surfaces are brought into contact with each other and fastened by a chuck so as to press the two blocks into pressure contact with each other, and held so that a circular hole is formed at the center thereof. And the reamer for taper hole processing is used for the circular hole (
It is inserted while rotating relative to a pair of blocks) to form a tapered hole. Each cross section of the taper hole formed in this way becomes a perfect circle. The cross section of the tapered recess of each block is an accurate semicircle. Therefore, the side wall surface 12 (FIG. 1) on the side of the tapered recess is ground very slightly. The polishing amount is about 0.01 to 0.5 mm, preferably 0.03 to 0.2 m
It is about m. The side wall surface 12 is polished in each block. Then, when they are aligned in opposite directions, the cross section formed by the tapered recesses is extremely slightly deformed from the true circle as shown in FIG.

Then, when the taper pin 3 is inserted there, both side surfaces of the taper pin 3 contact only the central portion of the taper recess 4 of each block 5, 5, and the upper and lower ends of the taper pin 3 are non-contact portions with extremely small gaps. 13 is formed. It should be noted that this gap is about the polishing margin of the side wall surface 12 described above. Therefore, the non-contact portion 13 can hardly be discriminated by the naked eye. Next, the pair of blocks are finished in perfect circles having the same diameter at their outer circumferences in a state where the blocks are aligned in opposite directions. This perfect circle is 2 more than the perfect circle of the keyway.
It is processed as small as / 100 to 3/100 mm. The taper of the taper hole inside each block 5, 5 is 1/50 as an example. When the taper hole is 1/50, many commercially available taper reamers can be used. At the same time, the 1/50 taper pin that matches this taper hole is
It is possible to use those already commercially available in large numbers for other applications. It suffices to form the threaded portion 2 on the outer periphery of the taper side end of such a commercially available taper pin and to provide the wrench hole 10 or the notch 11 on the end surface. Further, the wrench hole 10 and the like are not essential and may be omitted. According to the experiment, it was found that the taper pin does not rotate even if the nut is screwed onto the threaded portion 2 and the taper pin 3 is rotated without restraining the taper pin 3. It is presumed that this is because the contact resistance between the taper pin and the block prevents the taper pin from rotating around.

The key thus constructed can be used by cutting it at an appropriate position of the key according to the length of the key groove of the drive shaft 7 and the driven shaft 8 to be mounted. Then, the pair of blocks 5 and the taper pin 3 are combined and inserted into the key groove of the drive shaft 7 and the driven shaft 8 as shown in FIG. That is, the pair of blocks 5 are inserted so that the joint surface is located at the center of the semicircular key groove. And the fastening means 6
The nut that constitutes the taper pin 3 is screwed onto the threaded portion 2 of the taper pin 3, and the wrench hole 10 or the cutout portion 11 on the end surface of the taper pin 3 is also attached.
Then, the tip of a wrench or the tip of a screwdriver is fitted to prevent rotation, and the nut is rotated with a spanner or the like. Then, the taper pin 3 moves in the nut direction, and as a result, the upper and lower ends of the taper pin 3 also come into contact with the inner peripheral surface of the block 5 more and the non-contact portion 13 gradually disappears. A small gap 9 is formed between both blocks, and the gap between the block 5 and the driven shaft 8 and the drive shaft 7 disappears.

According to the experiment, the amount of rotation of the fastening means 6 between the state of FIG. 3 and the state of FIG. 4 is 0.5 rotation to 2 rotations when the module of the screw portion is 1. As a result, the pair of blocks are firmly fixed to the key groove.
At this time, the gap of the small gap 9 is about 0.01 to 0.03 mm, which is hardly discernible by the naked eye. The gap between the block 5 and the key grooves of the driven shaft 8 and the drive shaft 7 may be extremely large, or may be larger if the block 5 itself is large. When the taper pin has a manufacturing error such as a deformation, it is necessary to rotate the nut 6 more than the above. According to the experiment, by loosening the fastening means 6 (FIG. 2) in the state of FIG. 4, the pair of blocks 5 and 5 could be successfully removed from the key groove.

[0013]

[Modification] The present invention is not limited to the above-mentioned embodiment, and for example, the taper recessed portion 4 of each block 5 is used.
May be formed in an extremely slight ellipse. At this time, it may be formed so that the major axis of the ellipse coincides with the side wall surface 12. It is sufficient that the difference between the major axis and the minor axis is 0.01 mm to 0.5 mm. Note that the thickness is preferably 0.02 mm to 0.2 mm.

[0014]

The key of the present invention is slightly deformed from the perfect circle when the tapered concave portions 4 of the pair of blocks 5 are overlapped so as to face each other, and when the tapered pin 3 is inserted there. First, since the central portion of the tapered recess 4 in the circumferential direction contacts, the pair of blocks 5
By rotating the fastening means 6 in a state where the taper pin 3 and the taper pin 3 are inserted into the key groove, the taper pin 3 can be relatively smoothly moved in the axial direction with respect to the blocks 5 and 5. Thereby, the key can be easily fastened and fixed in the key groove by expanding the space between the pair of blocks 5. Then, there is no gap (backlash) between the key and the key groove, and the rotation of the drive shaft can be accurately transmitted to the driven shaft. Further, by loosening the fastening means, the key can be smoothly removed from the key groove.

Moreover, since the fastening means 6 is screwed to the threaded portion 2, anyone can easily attach the key, and the bearing of the drive shaft 7 and the driven shaft 8 can be impacted when the key is attached. There is no risk of damaging the bearing. Further, since the key of the present invention has a circular outer periphery when the pair of blocks 5 are overlapped, the key groove formed between the drive shaft and the driven shaft is formed by a tool such as a drill. It is enough to make it circular. Therefore, the key groove is extremely easy to manufacture. Further, the key of the present invention has a simple structure, is easy to manufacture, and is excellent in mass productivity.

[Brief description of drawings]

FIG. 1 is a perspective view showing components of a key of the present invention.

FIG. 2 is a side view showing an assembled state of the key of the present invention.

FIG. 3 is a cross-sectional view showing a usage state of the key of the present invention, showing a state before fastening the fastening means.

FIG. 4 is a cross-sectional view showing a usage state of the key of the present invention.

FIG. 5 is another embodiment of the taper pin 3 constituting the key of the present invention.

[Explanation of symbols]

 1 taper surface 2 screw part 3 taper pin 4 taper recess 5 block 6 fastening means 7 drive shaft 8 driven shaft 9 small gap 10 wrench hole 11 notch 12 side wall surface 13 non-contact part

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location F16D 1/04 1/02

Claims (3)

[Claims] 1. A taper pin (3) having an outer circumference having a circular cross section formed on a taper surface (1) and a threaded part (2) provided on an outer circumference of one end portion in a longitudinal direction, and a taper recessed portion aligned with the taper pin. (4) is formed on each side surface, and is screwed to the pair of elongated blocks (5) and (5) each having a semicircular cross-section with the same radius and the screw portion (2). Fastening means for axially moving the taper pin (3) relative to the blocks (5) and (5) by relative rotation, the pair of blocks (5) and (5) respectively. Of the tapered recesses (4) (4)
When the two are superposed so as to face each other, the inner circumferences of their axial cross sections are slightly deformed from the perfect circles, and thus the taper pin (3) is inserted into the taper recess (4) in the superposed state. At this time, the key is characterized in that a part of the outer peripheral surface of the taper pin (3) first comes into contact with the central portion in the circumferential direction of the taper recess (4) of each block (5) (5). 2. The key according to claim 1, wherein an arc of an inner circumference of an axial cross section of at least one of the blocks (5) is formed into an arc slightly shorter than a semicircle. 3. The key according to claim 2, wherein an inner circumference of an axial cross section of the block is formed in an arc shorter by 0.01 mm to 0.50 mm than a semi-circle.