JPH0719210A - Woodruff key - Google Patents

Abstract

PURPOSE:To provide a woodruff key that is able to prevent any fallout and dislocation from a key seat and, what is more, ease of machining and setting work. CONSTITUTION:A woodruff key 2 consists of a key body 2a made up into semicircular form and a pair of projections 2b installed projectingly in a direction extending a ridgeline equivalent to a semicircualr chord in this key body 2a. In addition, this projection 2b is formed in a part being projected out of a key seat 6 when the woodruff key 2 is inserted into this key seat 6 formed in a turning shaft 4. In this Woodruff key 2 constituted like this, when it is attached to the turning shaft 4, the paired projections 2b cane into contact with a wall surface 4a of the turning shaft 4, preventing any rotation of the Woodruff ket 2 from occurring. Therefore, when a rotary component is attached to the turning shaft 4, even if this component contacts with the l woodruff ket 2 which will in no case cause any dislocation and drop from the key seat 6 at all.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a half-moon key for connecting a rotary shaft and a rotary component such as a gear and a belt wheel to transmit torque between the rotary shaft and the rotary component.

[0002]

2. Description of the Related Art Conventionally, a half-moon key has been known as a mechanical component for connecting a rotary shaft and a rotary component such as a gear wheel and a belt wheel. The half-moon key is fitted in a half-moon shaped key groove formed on the wall surface of the rotary shaft, and the upper part of the half-moon key protruding from the key groove is engaged with the groove formed in the rotary shaft insertion hole of the rotary component. The torque is transmitted between the rotating shaft and the rotating parts.

By the way, in the half-moon key, when the half-moon key is fitted into the key groove, it is desirable that the upper surface of the half-moon key and the surface on which the key groove is formed are parallel to each other. However, in general, the fit between the keyway of the rotary shaft and the half-moon key is a loose fit in consideration of the strength of the rotary shaft and facilitating the attachment and detachment work of the key during assembly and disassembly. Therefore, when the rotary component is mounted on the rotary shaft, the rotary component comes into contact with the half-moon key to rotate the half-moon key, causing the half-moon key to be displaced, and in some cases, the half-moon key falls out of the key groove. There was a problem.

On the other hand, in order to solve such a problem, conventionally, for example, as described in Japanese Patent Application Laid-Open No. 54-150353, a side surface of the half-moon key is provided with a ridge line corresponding to the chord of the half-moon in the half-moon key. There is one in which parallel protrusions are provided, and when the half-moon key is mounted in the key groove, the protrusions are press-fitted into the key groove so that the fit between the half-moon key and the key groove becomes an interference fit.

[0005]

However, in such a half-moon key, since the fit between the half-moon key and the key groove is an interference fit, the half-moon key falls off from the key groove when the rotary component is mounted on the rotary shaft. Although there is no such a case, when the half-moon key is mounted on the rotary shaft, the protrusion has to be press-fitted into the key groove, which causes a problem that the mounting work is troublesome.

Further, in the case where a protrusion for interference fit is provided on the half-moon key as described above, if the protrusion is too high, the protrusion cannot be press-fitted into the key groove, or even if it is press-fitted into the key groove. There is a problem that the strength of the rotating shaft where the keyway is formed is deteriorated by applying extra force. Conversely, if the protrusion is too low, the fit between the half-moon key and the keyway will be an interference fit. However, there is a problem that it becomes meaningless to provide the protrusion. Further, when the protrusion is not formed parallel to the upper surface of the half-moon key, there is a problem that the upper surface of the half-moon key is inclined with respect to the surface in which the key groove is formed when press-fitting. In order to solve such a problem, the half-moon key must be processed with high accuracy so that the heights and positions of the projections do not vary when forming the projections, which is a problem that the processing is difficult.

Further, in such a half-moon key, since the projection is press-fitted into the key groove when it is mounted in the key groove, an initial stress is always applied to the key groove, and the strength of the rotary shaft in which the key groove is formed. Will be deteriorated. Therefore, there is also a problem that the rotary shaft must be designed in strength considering such deterioration in strength.

When the half-moon key is pressed into the keyway,
The protrusions may be scraped off by the inner wall of the keyway, which may cause burrs.The scraped metal pieces may enter the gap between the rotating shaft and rotating parts or other mechanical parts, damaging and deteriorating the parts. There are also problems such as causing unexpected failures.

The present invention has been made in order to solve these problems, and does not cause positional displacement or drop out of the key groove when mounting a rotary component on a rotary shaft, and facilitates processing and mounting work. Intended to provide a half-month key.

[0010]

SUMMARY OF THE INVENTION The present invention, which has been made to achieve the above object, comprises a rotary shaft and a rotary component which is mounted in a key groove formed in the rotary shaft and is disposed around the rotary shaft. A half-moon key that joins the key groove, the side surface of the upper part of the key projecting from the key groove when mounted in the key groove, abutting against the wall surface of the rotating shaft around the key groove, in the key groove of the half-moon key. The gist is a half-moon key, which is characterized by forming a protrusion that restricts rotation.

[0011]

In the half-moon key of the present invention having the above-described structure, when mounted in the keyway, the protrusion formed on the side surface abuts the wall surface of the rotating shaft around the keyway,
The rotation of the half-moon key in the key groove is restricted. Therefore, even when the rotary component hits the half-moon key when attaching the rotary component to the rotary shaft, the half-moon key does not rotate in the key groove, and as a result, unlike the conventional half-moon key that does not have a protrusion, When mounting the rotating parts, there will be no misalignment or falling out of the keyway.

The projection is formed on the side surface of the upper part of the half-moon key that protrudes from the key groove when the half-moon key is mounted in the key groove. Since the rotation within the keyway is restricted, it is not necessary to press fit the protrusion into the keyway when installing it, unlike the conventional protrusions for interference fit with the keyway. The fit between the key and the keyway may be a loose fit.

Therefore, when the half-moon key is attached to the key groove, it is sufficient to insert the half-moon key into the key groove, and the attaching operation can be easily performed. Further, in particular, when the half-moon key of the present invention is inserted into the key groove, the half-moon key is automatically positioned by the protrusion. Therefore, when inserting the half-moon key into the key groove, the position shift of the half-moon key with respect to the rotating shaft is important. There is no need to set it, and workability when the half-moon key is attached can be improved.

Further, since it is not necessary to press fit the protrusion when the half-moon key is mounted in the key groove, the strength of the rotary shaft is not deteriorated due to the press fit of the protrusion.
Moreover, since the projections are not scraped off by press fitting, it is possible to prevent deterioration of each part after mounting the rotary component.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. 1A and 1B are explanatory views showing the overall configuration of the half-moon key 2 of the present embodiment. FIG. 1A is a front view of the half-moon key 2, FIG. 1B is a right side view of the half-moon key 2, and FIG. It is sectional drawing showing the attachment state of 2 to the rotating shaft 4.

As shown in FIG. 1 (a), the half-moon key 2 of this embodiment has a key body 2a formed in a half-moon shape and a protrusion in a direction extending a ridge line corresponding to the chord of the half-moon of the key body 2a. It is composed of a pair of protrusions 2b provided. And
As shown in FIG. 1C, the protrusion 2b is formed on the side surface of the upper part of the key body 2a which protrudes from the key groove 6 when the half-moon key 2 is mounted on the key groove 6 formed on the rotary shaft 4. The width of the key body 2a as shown in FIG. 1 (b).
It is formed in the same width as.

In the half-moon key 2 of the present embodiment constructed as described above, when the half-moon key 2 is mounted in the key groove 6, the pair of projections 2b engages with the wall surface 4a of the rotary shaft 4 around the key groove 6. Therefore, the protrusion 2b restricts the rotation of the half-moon key 2 in the key groove 6.

Therefore, according to the half-moon key 2 of this embodiment,
When the half-moon key 2 is inserted into the key groove 6, the upper surface of the half-moon key 2 and the wall surface 4a of the rotating shaft 4 are automatically kept substantially parallel to each other. In this state, even if an external force is applied to the half-moon key 2 due to vibration, contact, etc., the half-moon key 2 does not move to the key groove 6
Since it does not rotate inside, unlike the conventional half-moon key that is not provided with a protrusion, it will not be displaced or fall out of the key groove 6 due to an external force.

When the rotation of the meniscus key 2 is restricted by the protrusion 2b as described above, the length of the protrusion 2b may be such that it can come into contact with the wall surface 4a of the rotary shaft 4, so that the length is set to that length. Strict accuracy is not required, and in the half-moon key 2 of this embodiment, the projection 2b is provided in the direction of extending the ridge line corresponding to the chord of the half-moon of the key body 2a. Is the same as the width of the key body 2a.

Therefore, when manufacturing the meniscus key 2 of this embodiment, it is sufficient to carry out processing with the same degree of accuracy as in the case of manufacturing a conventional meniscus key having no protrusions, such as press working and cold forming. The key body 2a and the protrusion 2b can be simultaneously formed by processing, injection molding, or the like.

Further, the protrusion 2b is not pressed into the key groove 6 when it is mounted on the rotary shaft 4, and the width of the protrusion 2b is the same as that of the key body 2a. Therefore, when the protrusion 2b is used as a substitute for the conventional half-moon key. The keyway 6 formed on the rotary shaft 4,
In the groove formed in the rotary shaft insertion hole of the rotary component (not shown),
It can be used as it is without any processing.

Furthermore, the fit between the half-moon key 2 and the key groove 6 may be a loose fit, and when the half-moon key 2 is mounted on the rotary shaft 4, it is not necessary to press the half-moon key 2 into the key groove 6 and therefore, the half-moon key. The work of mounting the key 2 can be easily performed. When the half-moon key 2 is mounted on the rotary shaft 4, unless the half-moon key 2 is press-fitted into the key groove 6, there are problems such as a decrease in strength of the rotary shaft 4 caused by the press-fitting and a decrease in strength due to the occurrence of burrs. Therefore, it is possible to prevent deterioration of the quality of the device in which the half-moon key 2 of this embodiment is used.

Next, a case where the half-moon key 2 of this embodiment is used for a connecting portion between a camshaft of a fuel injection pump for a diesel engine and an automatic timer attached to the camshaft will be described. FIG. 2 is an explanatory diagram showing the overall configuration of a diesel engine fuel injection pump in which an automatic timer is attached to a camshaft.

In FIG. 2, the fuel injection pump 10 has the same number of fuel pressurizing mechanisms as cams and plungers as the number of cylinders, and the fuel pressurizing mechanisms are arranged in series so as to operate in the combustion order. Is a well-known in-line injection pump that controls fuel injection by moving a plunger up and down.

The fuel injection pump 10 pressurizes the fuel sucked up from the fuel tank by the feed pump 10a provided on the lower side surface of the fuel injection pump 10 by the fuel pressurizing mechanism inside the fuel injection pump 10. The fuel compressed to a high pressure is sent to the nozzle through the injection pipe connected to the delivery valve holder 10b provided at the upper part of the main body of the fuel injection pump 10 and injected into the combustion chamber.

Further, the automatic timer 16 is arranged between the drive shafts of the engine and the injection pump so that the fuel injection timing becomes appropriate with respect to the crank angle of the engine according to the engine speed and the load. It is well known to automatically adjust the phase. As shown in FIG. 2, one end of a cam shaft 14 that drives the vertical movement of the plunger is provided so as to project from the fuel injection pump 10. The camshaft 14 includes an automatic timer 16 attached to the camshaft 14 by the half-moon key 2 and a round nut 20, and an automatic timer 16.
Is coupled to a shaft of a diesel engine (not shown) via a coupling 18 connected to the shaft. Therefore, the camshaft 14 rotates according to the rotation of the shaft of the diesel engine. Note that, in FIG. 2, the camshaft 14, the half-moon key 2 and the round nut 20 shown by the dotted line are hidden by the automatic timer 16 and therefore cannot actually be seen from the outside.

Next, as shown in FIG.
As shown in FIG. 3, a conical taper portion 14a is formed,
Further, a threaded portion 14b into which a round nut 20 for fixing the automatic timer 16 to the tapered portion 14a is screwed is formed at the tip of the tapered portion 14a. A key groove 14c for inserting the half-moon key 2 is formed in the tapered portion 14a.

On the other hand, at the center of the automatic timer 16, an insertion hole 16a for inserting the camshaft 14 is formed in a conical shape in conformity with the shape of the tapered portion 14a of the camshaft 14, and the insertion hole 16a is further formed. Has
A key groove 16b for engaging with the meniscus key 2 attached to the camshaft 14 is formed.

The procedure for mounting the automatic timer 16 on the camshaft 14 projecting from the fuel injection pump 10 will be described below. First, after positioning the cam shaft 14 so that the key groove 14c formed in the tapered portion 14a of the cam shaft 14 faces upward, the key groove 14c
Insert the half-moon key 2 into. At this time, the half-moon key 2 is attached to the camshaft 14 so that the surface of the tapered portion 14a and the upper surface of the half-moon key 2 are parallel to each other by the projection 2b.

Next, the camshaft 14 is inserted into the key groove 16b formed in the insertion hole 16a of the automatic timer 16.
The camshaft 14 is inserted through the insertion hole 16 so that the upper portion of the meniscus key 2 protruding from the tapered portion 14a of the
Insert into a. Then, the taper portion 1 of the camshaft 14
4a and the inner surface of the insertion hole 16a are brought into contact with each other, and the round nut 20 is attached to the threaded portion 14b of the camshaft 14 from the back side of the automatic timer 16 so as to prevent the camshaft 14 from coming off.

As described above, according to the half-moon key 2 of the present embodiment, when the half-moon key 2 is inserted into the key groove 14c, the half-moon key 2 is automatically positioned by the projection 2b provided on the half-moon key 2, so that the half-moon key 2 is positioned. Even when the key 2 is attached to a portion such as the taper portion 14a where the surface is inclined, it is not necessary to check the attachment state of the half-moon key 2 one by one, and the work of attaching the half-moon key 2 is facilitated.

When the camshaft 14 is inserted into the insertion hole 16a, the upper portion of the half-moon key 2 protruding from the tapered portion 14a and the key groove 16b provided in the insertion hole 16a are fitted to each other. The edge of 16b or the like easily contacts the meniscus key 2 and an external force may be applied to the meniscus key 2. However, since the meniscus key 2 of the present embodiment is provided with the projection 2b, such an external force is not generated. Half moon key 2 even if added
Does not rotate to cause positional displacement, and some contact or vibration will hinder this work unless the half-moon key 2 receives a shock enough to fall from the inserted key groove 14c. There is no such thing as. Therefore, according to the half-moon key 2 of this embodiment, the assembling work of the part using the half-moon key 2 can be easily performed.

In the half-moon key 2 of this embodiment,
The protrusion 2b is provided in the direction of extending the ridge line corresponding to the chord of a half moon (hereinafter referred to as vertical type), but as shown in FIG. 4, the protrusion 30b is provided on the half-moon shaped side surface of the key body 30a (hereinafter
It may be referred to as a horizontal type). However, in the case of the horizontal half-moon key 30, since the width of the portion provided with the protrusion 30b is different from the width of the portion inserted into the key groove, the horizontal half-moon key 30 cannot be manufactured by press working, which requires some labor in manufacturing. Further, in the case of the horizontal half-moon key 30, since the width of the portion provided with the protrusion 30b needs to correspond to the width of the key groove of the rotary component attached to the rotary shaft, it is used as it is as a substitute for the conventional half-moon key. However, other than that, the same effect as that of the vertical type described above can be obtained. In the case of the horizontal half-moon key 30, the protrusion 30b may be formed only on one side surface of the half-moon key.

Further, in the present embodiment, it has been explained that when the meniscus key 2 is mounted in the key groove 6 of the rotary shaft 4, the pair of projections 2b abut on the wall surface of the rotary shaft 4, but the projection 2b.
Does not necessarily have to come into contact with the wall surface of the rotary shaft 4 when the half moon key 2 is mounted in the key groove 6 of the rotary shaft 4.
It suffices that when is rotated in the key groove 6, it comes into contact with the wall surface of the rotating shaft 4 to regulate the rotation.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a half-moon key according to an embodiment.

FIG. 2 is an explanatory diagram showing an overall configuration of a fuel injection pump for a diesel engine to which the half-moon key of the embodiment is applied.

FIG. 3 is an explanatory diagram showing a mounting state of a half-moon key to a fuel injection pump.

FIG. 4 is an explanatory diagram illustrating another configuration example of a half-moon key.

[Explanation of symbols]

2, 30 ... Half-moon key 2a, 30a ... Key body 2
b, 30b ... Protrusion 4 ... Rotating shaft 4a ... Wall surface 6 ... Key groove 10 ... Fuel injection pump 14 ... Camshaft 16 ... Automatic timer

Claims (1)

[Claims] 1. A key groove formed on a rotating shaft,
A half-moon key for connecting the rotary shaft and a rotary component arranged around the rotary shaft, wherein the half-moon key is rotated around the key groove on a side surface of an upper part of the key protruding from the key groove when the key is attached to the key groove. A half-moon key, wherein the half-moon key is formed so as to come into contact with a wall surface of the shaft to restrict rotation of the half-moon key in the key groove.