JP4214762B2 - Assembling the torque transmitter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of assembling a torque transmission tool that can be used when a gear, a pulley, or the like is attached to a shaft.
[0002]
[Prior art]
One of the typical methods used to attach parts such as gears and pulleys to shafts such as rotating shafts is to use an outer diameter that is not smaller than the diameter of the center hole of the gear or pulley. It is to press-fit the shaft having it and make it an interference fit state. When this press-fitting method is used, the center hole formed in the gear or pulley is a simple circular hole, and the shaft may be a simple column, so the shape is simple and easy to process. If it is press-fitted into the pulley, it is difficult to remove it, so it is not easy to replace the gear when the tooth surface of the gear is damaged.
[0003]
Also, in recent small motors, an encoder for measuring the rotational position of the motor is often provided at one end of the shaft, so one end of the shaft is encased inside the motor housing and not exposed to the outside. When the shaft is press-fitted into the center hole of the gear or pulley, one end of the shaft cannot support the axial force acting on the shaft. It is impossible to combine etc.
[0004]
As a typical attachment method for easily removing the gear and pulley from the shaft, as illustrated in FIG. 4, the D-cut surface 3 is processed at the end of the shaft 2 of the motor 1, and the gear 4 is There is a method in which the center hole 5 is fitted in a gap, and a fixing screw 6 is screwed into a screw hole formed in a radial direction in a part of the gear 4 and the tip thereof is engaged with the D-cut surface 3 of the shaft 2.
[0005]
Furthermore, as another mounting method, as illustrated in FIG. 5, key grooves 7 and 8 are formed in the end portion of the shaft 2 and the center hole 5 of the gear 4, respectively, and the key 9 is pivoted in the key grooves 7 and 8. There is also a method in which the key 9 and the gear 4 with respect to the shaft 2 are prevented from coming off by two or more fixing screws 6 inserted in the direction and further screwed in the radial direction.
[0006]
However, in the conventional mounting method shown in FIGS. 4 and 5, the fixing screw 6 used in one or more is not only a stopper for the gear 4 and the key 9, but also the tip of the fixing screw 6. And at least a part of the torque may be transmitted at the contact portion with the D-cut surface 3 or the like engaged therewith, and in such a case, a large force that varies in the rotation direction acts on the contact portion to make contact. There is a problem that play in the rotation direction is likely to occur due to the deformation of the portion. Therefore, it is generally impossible to transmit a large torque by the structure as shown in FIGS.
[0007]
[Problems to be solved by the invention]
In view of the above-described problems in the prior art, the present invention makes it easy to attach and detach gears, pulleys, and the like to the shaft, and does not cause any deformation or loosening in a state where they are attached to the shaft. It is an object of the present invention to provide a method for assembling a torque transmission tool having a novel structure that can reliably transmit torque.
[0008]
[Means for Solving the Problems]
As a means for solving this problem, the present invention provides a method for assembling a torque transmitting tool according to claim 1 of the claims.
[0009]
According to the torque transmitting device assembly method of the present invention, the torque transmitting device is related to the annular support portion, the torque transmitting portion acting like a key, and the side of the connected body such as a gear or a pulley at the tip. Since the hook-shaped retaining portion to be joined is integrated and the retaining means for the shaft is additionally provided, the shaft and the connected body can be detachably connected. Therefore, work such as replacement of the connected body is facilitated.
[0010]
In addition, since torque is transmitted from the D-cut surface of the shaft to the key groove of the connected body through the torque transmitting portion acting like a key, even if there is a low strength portion such as a retaining means, Since no torque acts there, there is no risk of deformation of the low strength portion or backlash in the rotational direction.
[0011]
It is desirable that the cross-sectional shape of the torque transmission part is a rectangle like a normal key. As a retaining means for the support portion, a retaining screw that engages with the shaft by screwing into a screw hole formed in the support portion can be used. In this case, if an annular groove or hole that engages the tip of the retaining screw is formed on the surface of the shaft, the retaining function is further ensured. If necessary, the torque transmission part can be formed to extend into the hole of the support part. Thereby, the strength of the transition part between the torque transmission part and the support part increases.
[0012]
Typical examples of the connected body that can be connected to the shaft by using the torque transmitting device of the present invention are a transmission gear and a pulley.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Next, a preferred embodiment of the method for assembling the torque transmitting device of the present invention will be described in detail with reference to FIGS. FIG. 1 is a perspective view showing an external appearance of only a torque transmission tool 10 according to an embodiment of the present invention. The torque transmission tool 10 has a key groove 8 on the shaft 2 of the motor 1 as described above. The state where the gear 4 is attached is shown in FIG. 2 is disassembled, and each part of the torque transmission tool 10, the gear 4 having the shaft 2 and the keyway 8 of the motor 1 related thereto, and the retaining screw 18 described later is respectively provided. 3 is an exploded perspective view of FIG. 3 developed on a common axis.
[0014]
As is clear from these drawings, the torque transmitting device 10 of the embodiment shown in FIG. 1 is detachably fitted to the shaft 2 of the motor 1 with a minute gap remaining (gap fitting). A cylindrical (generally annular) support portion 11, and an axially projecting and extending from one end surface 15 of the support portion 11, and a key integrally formed with the support portion 11. A torque transmission part 12 having a rectangular cross section and a retaining part 13 formed by bending in a hook shape toward the outside in the perpendicular direction at the tip (free end) of the torque transmission part 12 are provided.
[0015]
The cylindrical support portion 11 is provided with a center hole 14 having an inner diameter of substantially the same size so as to be fitted to the shaft 2 with a gap. The torque transmitting portion 12 extending in the direction is configured such that about half of the sectional area of the torque transmitting portion 12 itself overlaps the axial projection surface of the center hole 14. However, when it is necessary to further increase the strength of the torque transmission tool 10, a part of the torque transmission part 12 may be extended to the inside of the center hole 14. In this case, the center hole 14 is not a simple circular hole, but has a protrusion protruding inward in the radial direction as a part of the torque transmitting portion 12. In this case, the D-cut of the shaft 2 is also provided. The axial length of the surface 3 is increased so as to match the protrusion.
[0016]
The distance (interval) between the end surface 15 of the support portion 11 and the axial inner surface 16 of the retaining portion 13 formed at the tip of the torque transmission portion 12 (referred to as a clamp portion 19) is the gear 4 ( Since this may be a pulley or the like, it is generally set to a size substantially the same as the thickness in the axial direction of a body to be connected). In addition, since the center of the center hole 14 formed in the support part 11 does not necessarily coincide with the center of the support part 11 as a whole, the center hole 14 generally does not act on the shaft 2. What is necessary is just a hole by which a clearance gap is fitted in a state.
[0017]
Further, a screw hole 17 is formed in the cylindrical support portion 11 in the radial direction, and a retaining screw 18 as clearly shown in FIG. 3 can be screwed together. One screw hole 17 and one screw 18 may be provided, but it goes without saying that a plurality of screw holes 17 and screws 18 may be provided. Although not shown, an annular groove or hole with which the tip of the screw 18 engages may be formed in a part of the shaft 2 in order to completely prevent the screw 18 from coming off.
[0018]
Since the torque transmission tool 10 of the illustrated embodiment is configured as described above, when the gear 4 is assembled to the shaft 2 using the torque transmission tool 10, first, the torque transmission unit 12 of the torque transmission tool 10 is connected to the shaft 2. Clamping the torque transmitting device 10 by inserting it into the central hole 5 of the gear 4 having substantially the same size inner diameter and having the keyway 8 formed therein and moving them relatively radially. The gear 4 is inserted into the portion 19. When the gear 4 is rotated with respect to the torque transmission tool 10 in this state, the torque transmission portion 12 having a cross-sectional shape like a key is fitted into the key groove 8 of the gear 4 and the gear 4 is a cylindrical support portion. 11 and the inner surface 16 of the retaining portion 13 are completely dropped into the clamp portion 19 and sandwiched between these surfaces, so that the gear 4 is pivoted with respect to the torque transmission tool 10. It becomes impossible to move relatively both in the direction and in the rotational direction.
[0019]
Since the center hole 14 of the torque transmitting tool 10 and the center hole 5 of the gear 4 that are coupled so as to be constrained to each other in this manner are aligned with each other as having the same diameter and coaxial center, a continuous center hole is formed. The tip of the shaft 2 of the motor 1 is inserted into the continuous center holes 14 and 5 and the gap is fitted. At this time, the torque transmission part 12 such as a key of the torque transmission tool 10 is matched with the D-cut surface 3 of the shaft 2.
[0020]
Finally, the screw 18 screwed into the screw hole 17 is lightly tightened to protrude inward, thereby preventing the torque transmitting tool 10 from coming out of the shaft 2. In this way, since the torque transmission tool 10 is prevented from moving in the axial direction relative to the shaft 2, the hook shape at the tip of the torque transmission part 12 that is a part of the torque transmission tool 10 is formed. Thus, the retaining portion 13 that catches the side surface 20 of the gear 4 can reliably prevent the gear 4 from slipping out of the shaft 2.
[0021]
The torque transmission tool 10 of the illustrated embodiment can be assembled to the shaft 2 and the gear 4 very simply as described above, and the gear 4 can be securely attached to the end of the shaft 2 as well as the retaining screw 18. Since the assembly of the torque transmission tool 10 and the gear 4 can be extracted from the shaft 2 only by loosening the gear, it is possible to easily separate them after the extraction. Therefore, it is very easy to attach / detach the gear 4 and the like to / from the shaft 2 and replace it.
[0022]
Moreover, the torque transmitted from the shaft 2 to the gear 4 includes the D-cut surface 3 of the shaft 2, the torque transmission part 12 of the torque transmission tool 10 in surface contact with the D-cut surface 3, and the torque Since it is transmitted through the wall surface of the key groove 8 of the gear 4 that is in surface contact with the transmission portion 12, torque is applied to the retaining screw 18 or a part of the shaft 2 with which the tip contacts. The force in the rotational direction due to transmission does not act. Therefore, since there is no possibility that such a relatively low strength portion is deformed, the torque transmitting device of the present invention can transmit a very large torque.
[Brief description of the drawings]
FIG. 1 is a perspective view showing only a torque transmission tool of an embodiment.
FIG. 2 is a perspective view showing an assembled state.
FIG. 3 is an exploded perspective view showing a developed state.
FIG. 4 is a perspective view showing a conventional technique.
FIG. 5 is a perspective view showing another conventional technique.
[Explanation of symbols]
2 ... shaft 3 ... D cut surface 4 ... gear (or connected body such as pulley)
DESCRIPTION OF SYMBOLS 8 ... Key groove 10 ... Torque transmission tool 11 ... Cylindrical support part 12 ... Torque transmission part 13 shaped like a key ... Saddle-shaped retaining part 14 ... Center hole 18 ... Retaining screw 19 ... Clamp part

Claims (6)

In the assembling method of the torque transmitting tool for assembling the coupled body to the shaft using the torque transmitting tool,
The torque transmitting tool includes an annular support portion having a hole that is fitted in a gap so that torque does not act on the shaft, and protrudes from one end surface of the support portion and extends in the direction of the shaft. said torque acts as a key by which a portion that fits against the surface and the keyway formed in the holes of the connecting member to surface contact with the D-cut surface formed on the shaft A torque transmitting portion that transmits from the shaft to the connected body, and a hook-shaped disconnection that is bent at the tip of the torque transmitting portion and engages the side surface of the connected body to prevent the connected body from coming off. A stopper is integrated with the stopper, and a retaining means for the shaft of the support is attached to the shaft.
The torque transmitting portion is inserted into the hole of the coupled body and fitted into the key groove, and the coupled body is sandwiched between the end surface of the support portion and the inner surface of the retaining portion, thereby The tip of the shaft is inserted into the hole of both of the connected body and the torque transmission tool which are coupled so as to restrain each other, and the gap is fitted into the hole so that the torque transmission tool matches the D-cut surface of the shaft. is allowed and then by tightening the retaining means, the method of assembling the torque transmitting device, wherein the torque transmitting device is prevented from getting out from the shaft. The method for assembling a torque transmission tool according to claim 1, wherein an axial sectional shape of the torque transmission portion is a rectangle. 3. The retaining means of the support part according to claim 1 or 2, comprising: a screw hole formed in the support part; and a retaining screw that is screwed into the screw hole and engages the shaft. An assembling method of the torque transmitting device as a feature 4. The torque transmission according to claim 3, wherein the retaining means of the support portion includes an annular groove or hole formed in the shaft so that a tip of the retaining screw is engaged. How to assemble the tool. 5. The method of assembling a torque transmission tool according to claim 1, wherein the torque transmission part is formed so as to extend into the hole of the support part. 6. The method for assembling a torque transmitting device according to claim 1, wherein the coupled body is one of a gear and a pulley.

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