JP2007278230A - Cotter installing jig - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent damage of a cotter and a valve stem at a time of cotter installation. <P>SOLUTION: This cotter installing jig 20 is provided with a main body 21 aligned on the valve steam 7, making a retainer 9 fitted thereon and pushing down the same, a piston member 22, a shaft part 29 extending from the piston member 22 and having an upper end part of the valve stem 7 fitted thereon, an energizing member energizing the piston member, and a projection part provided on an inner wall of the main body. The cotter is retained by the projection part and the shaft part not to drop form a gap between the projection part and the shaft part when the projection part and the shaft part oppose, and the cotter drops from the gap and is supplied when the projection part oppose to the valve stem. Side of the cotter and the valve stem for dropping and supplying the cotter is inhibited to prevent scratch thereof. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cotter assembling jig, and more particularly, to a cotter assembling jig for assembling a cotter in a gap between a valve stem of an intake valve or an exhaust valve of an internal combustion engine and a retainer.

  In general, an intake valve and an exhaust valve are attached to a cylinder head of an engine (internal combustion engine), and the intake valve and the exhaust valve are each urged in a closing direction or an upward direction by a compressed valve spring. In order to realize such an assembled state, a retainer for receiving the pressing force of the valve spring is attached to the upper end portion of the valve stem of the intake valve or the exhaust valve, and the valve spring is interposed between the retainer and the cylinder head. Arranged in a compressed state. The retainer is attached to the upper end portion of the valve stem through a half-tapered cotter divided into two in the circumferential direction. The cotter is held by the valve stem, and the protrusion formed on the inner peripheral surface is inserted into the cotter groove of the valve stem, and the retainer fitted to the outer periphery of the cotter is pulled out of the valve stem by the pressing force of the valve spring. Fix so that there is no.

  When the cotter is assembled in the gap between the retainer and the valve stem, the retainer is pushed down to compress the valve spring, and the cotter groove of the valve stem is positioned above the retainer. Then, the cotter is held by the valve stem in accordance with the cotter groove of the valve stem, the retainer is released, the retainer is raised by the upward force of the valve spring, and the retainer is fitted to the outer peripheral side of the cotter.

  However, in actuality, this cotter assembly work is a difficult task that requires considerable cans and knacks, and the problem of cotter assembly is one of the typical and chronic problems that those skilled in the art have had in the past. . First, when compressing the valve spring by pushing down the retainer, if the valve spring is not compressed evenly around the entire circumference, the retainer tilts or decenters, and the gap between the retainer and the valve stem does not become uniform in the circumferential direction. On the small side, the cotter does not fit properly, and the worst part protrudes, and on the side where the gap is large, the cotter bites and the fitting does not fit properly. Further, while compressing the valve spring, it is very difficult to keep the retainer concentric with the valve stem against the reaction force and keep the gap between the retainer and the valve stem uniform all around. In actual work, the retainer often sways and tends to tilt or decenter. If the cotter does not fit properly or evenly, an uneven load will be applied to the valve stem, causing seizure of the valve stem, impairing the proper operation of the valve, deteriorating engine performance and exhaust gas performance, and increasing oil consumption. There is a risk of doing. Although the cotter assembly failure can be detected by inspection at the engine production stage, it is a rare event, and it is desirable to fundamentally solve the cause. In addition, in the maintenance stage after being on the market, there are not so many cases that heavy maintenance is required to remove the intake / exhaust valves, so there is a tendency not to regard it as a problem and the problem is becoming chronic as well.

  Patent Document 1 discloses a cotter mounting jig that can help solve the above problems. The cotter mounting jig includes a cotter pressing member that is slidably disposed in the main body. When attaching the cotter, the retainer is pushed down while being centered by the main body in a state where the cotter is inserted and disposed in the cotter insertion hole of the retainer. The cotter is pushed open in the radial direction by the cotter pressing member and lowered until it passes through the engagement groove of the valve stem. The tip of the valve stem is inserted into the insertion hole of the cotter pressing member. Thereafter, the cotter mounting jig is raised, the retainer is raised and restored by the spring force of the valve spring, and the engagement protrusion of the cotter is engaged with the engagement groove of the valve stem.

JP 2000-190146 A

  However, in the cotter mounting jig described in Patent Document 1, the cotter is inserted and disposed in advance in the cotter insertion hole of the retainer, and the cotter is pushed down from the tip of the valve stem to below the engagement groove of the valve stem. The cotter moves while being dragged by the valve stem, which may damage the cotter and the valve stem. In addition, since the valve stem is inserted into the insertion hole of the cotter holding member after the retainer is pushed down to some extent, the valve stem is not centered with respect to the valve stem before being inserted into the insertion hole of the cotter holding member. The cotter fits on the outer peripheral side of the valve stem and slides on the outer peripheral side of the valve stem. As a result, the cotter is forcibly inserted into the valve stem and dragged, and the cotter and the valve stem may be greatly damaged.

  Therefore, the present invention has been made in view of such a problem, and an object thereof is to provide a cotter assembling jig capable of preventing damage to the cotter and the valve stem at the time of assembling the cotter.

  Another object of the present invention is to provide a cotter assembling jig that can supply a cotter at an appropriate timing when assembling the cotter, and is simple in operation and simple in structure.

  In order to achieve the above object, according to one aspect of the present invention, a retainer is pushed down while compressing a valve spring disposed on the outer peripheral side of a valve stem of an internal combustion engine, and a cotter is assembled in a gap between the valve stem and the retainer. A cotter assembling jig, which is arranged in alignment above the valve stem, and a cylinder-shaped body for fitting and pushing down the retainer, and a piston member movably inserted into the body A shaft that extends downward from the piston member and engages the upper end of the valve stem at the lower end, a biasing member that is disposed within the main body and biases the piston member downward, and the piston Provided on the inner wall of the main body at a position below the member, and depending on the position of the piston member with respect to the main body, A protrusion that can be opposed to the shaft with a predetermined gap in the direction, and when the protrusion faces the shaft, the cotter is prevented from dropping from the gap between the protrusion and the shaft. When the protrusion is opposed to the valve stem, the cotter is dropped from the gap between the protrusion and the valve stem, and the cotter is supplied to the gap between the valve stem and the retainer. It is characterized by being configured.

  According to this aspect of the present invention, the cotter can be dropped and supplied to the gap between the retainer and the valve stem. Therefore, there is no operation for forcibly fitting the cotter into the valve stem, and the distance that the cotter slides relative to the valve stem is a slight distance until the supplied cotter rises and fits into the cotter groove. Can be suppressed. Thereby, the damage of a cotter and a valve stem can be suppressed to the minimum.

  Preferably, the cotter assembling jig is configured such that the protrusion of the cotter supplied to the gap between the valve stem and the retainer is positioned at least below the cotter groove of the valve stem. The valve stem faces the valve stem, and the cotter is configured to fall.

  Thereby, the cotter can be dropped and supplied at an appropriate timing, the sliding of the cotter with respect to the valve stem can be suppressed, and the cotter and the valve stem can be prevented from being damaged.

  Preferably, there is further provided a weight that is movably provided below the piston member in the main body and presses the cotter held in the main body downward by its own weight.

  Thereby, for example, even when the cotter is wet with oil, the cotter can be peeled off from the adhesion by the oil, and the cotter can be reliably dropped.

  Preferably, the minimum inner diameter of the protruding portion is set to be equal to or smaller than the upper end inner diameter of the center hole of the retainer.

  This makes it possible to accurately drop the dropped cotter into the gap between the retainer and the valve stem without hitting the upper surface of the retainer.

  Preferably, the protruding portion has a tapered shape that gradually reduces the inner diameter as it goes downward. As a result, the cotter can be dropped smoothly.

  Preferably, the cotter assembling jig is aligned with the valve stem when the lower end portion of the shaft portion is fitted to the upper end portion of the valve stem.

  As a result, each part of the jig can be operated with the valve stem as a reference axis, and in particular, the retainer can be lowered and raised while being held coaxial with the valve stem.

  Preferably, the main body is fitted to the retainer after the lower end portion of the shaft portion is fitted to the upper end portion of the valve stem.

  If it carries out like this, it will become possible to align a jig | tool with a valve stem before fitting to the main body of a retainer, and it becomes possible to hold | maintain a retainer coaxially with a valve stem from the time of fitting to a main body.

  Preferably, the shaft portion has a larger diameter than the valve stem.

  According to the present invention, it is possible to prevent damage to the cotter and the valve stem at the time of assembling the cotter, to supply the cotter at an appropriate timing, and to provide a cotter assembling jig that is simple in operation and simple in structure. Excellent effect is exhibited.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 shows a cotter assembling jig according to an embodiment of the present invention, and FIG. 2 shows a valve operating mechanism of an engine to be used for the jig.

  As shown in FIG. 2, the intake valve 2 is attached to the cylinder head 1 with the valve spring 3 being closed. The intake valve 2 normally closes the intake port 4 formed in the cylinder head 1 as illustrated, and opens the intake port 4 when pushed down from the illustrated position by a camshaft or the like (not illustrated). The intake valve 2 is guided to move up and down by a guide pipe 5 attached to the cylinder head 1. The intake valve 2 integrally includes an umbrella-shaped valve body 6 that opens and closes an outlet of the intake port 4 located on the lower surface of the cylinder head 1 and a valve stem 7 that extends coaxially upward from the valve body 6. A retainer 9 is attached to the upper end portion of the valve stem 7 via a cotter 8, and the valve spring 3 is arranged in a compressed state between the retainer 9 and the cylinder head 1. The valve spring 3 is disposed on the outer peripheral side of the valve stem 7.

  As shown in FIG. 3, at the upper end portion of the valve stem 7, a half-cylindrical cotter 8 is fitted to the outer peripheral surface of the valve stem 7. A cotter groove 10 along the entire circumference is provided on the outer peripheral surface of the valve stem 7, and a protrusion 11 that engages with the cotter groove 10 is provided on the inner peripheral surface of the cotter 8. In the present embodiment, a so-called medium bead cotter in which one protrusion 11 is located in the axially intermediate portion of the cotter 8 is employed. However, a cotter having a protrusion at the upper end (so-called upper bead) or a cotter having a plurality of protrusions. Can also be adopted. Further, in the present embodiment, a so-called externally held cotter in which a portion other than the protrusion 11 is held on the outer peripheral surface of the valve stem is adopted, but a so-called internally held cotter in which the entire cotter is engaged with the cotter groove is adopted. May be. The outer peripheral surface of the cotter 8 is formed in a tapered shape with a diameter decreasing toward the lower side, and a retainer 9 having a center hole 9A having a similar tapered shape is fitted to the outer peripheral surface of the cotter 8. In the illustrated assembled state, the valve spring 3 presses the retainer 9 upward, and this pressing force pushes the cotter 8 radially inward by the wedge action of the taper to bring it into close contact with the valve stem 7. As a result, the protrusion 11 of the cotter 8 does not detach from the cotter groove 10, and the retainer 9 is maintained in a state of being prevented from coming off from the valve stem 7. As shown in the drawing, the cotter 8 is assembled in a gap (hereinafter referred to as a cotter gap) 40 between the retainer 9 and the valve stem 7.

  As can be seen, the central hole 9A of the retainer 9 is larger in diameter than the valve stem 7, there is a cotter gap 40 between them, and the retainer 9 is pressed upward by the valve spring 3, When assembling the cotter, problems such as the inclination and eccentricity of the retainer 9 and the unevenness of the cotter gap 40 occur as described above. The jig according to the present embodiment solves these problems, and can hold the cotter gap 40 between the retainer 9 and the valve stem 7 evenly in the circumferential direction and assemble the cotter 8 properly.

  Next, the cotter assembling jig of this embodiment will be described with reference to FIG. The cotter assembling jig 20 includes a cylindrical main body 21, a piston member 22 movably inserted into the main body 21, and a spring 23 as an urging member disposed in the main body 21. The main body 21 extends from the lower end side (one end side) to the upper end side (the other end side) along the direction of the central axis C, has a circular cross section, the lower end portion is opened, and the upper end portion is closed by the lid plate 24. ing. A cylinder chamber 25 is defined in a substantially upper half of the main body 21, and a piston member 22 is slidably disposed in the cylinder chamber 25 in the vertical direction. A spring 23 made of a coil spring is disposed in the cylinder chamber 25 in a compressed state, and the piston member 22 is urged downward by the spring 23.

  A retainer hole 26 for fitting the retainer 9 is formed at the lower end of the main body 21 coaxially with the main body 21. The retainer hole 26 is opened downward and has a hole diameter substantially the same as the outer diameter of the retainer 9. The retainer hole 26 is defined by a peripheral side wall 27 that engages with the outer peripheral side surface of the retainer 9 and an annular contact surface 28 that contacts the upper surface of the retainer 9. The contact surface 28 is a plane perpendicular to the axis C.

  The piston member 22 integrally includes a shaft portion 29 having a circular cross section extending coaxially downward from the center portion thereof, and the upper end portion of the valve stem 7 is fitted to the lower end portion or the lower end surface of the shaft portion 29. A stem hole 30 is formed coaxially with the main body 21. Similarly to the retainer hole 26, the stem hole 30 is opened downward and has a hole diameter substantially the same as the outer diameter of the upper end portion of the valve stem 7. The stem hole 30 is defined by a peripheral side wall 31 that engages with the outer peripheral side surface of the valve stem 7 and a contact surface 32 that contacts the upper end surface of the valve stem 7. The contact surface 32 is a plane perpendicular to the axis C.

  A projecting portion 33 projecting radially inward is provided on the inner wall of the main body 21 located between the cylinder chamber 25 and the retainer hole 26. In the present embodiment, the protruding portion 33 is formed integrally with the main body 21, but may be provided separately from the main body 21. The protrusion 33 has a tapered shape such that its inner diameter gradually decreases as it goes downward in the axial direction, and starts at a boundary position with the cylinder chamber 25 and ends at a boundary position with the retainer hole 26. Therefore, the protrusion 33 has a maximum protrusion at its lower end (this position is referred to as a protrusion end 34) and has a minimum inner diameter D1.

  A cylindrical weight 35 is slidably fitted into the shaft portion 29 of the piston member 22. The weight 35 is positioned at least above the projecting end 34 of the projecting portion 33, and its lower end portion is formed in a tapered shape. As shown in the figure, the corner portion between the cylindrical surface and the tapered surface of the weight 35 projects. When hooked on the portion 33, the lowering of the piston member 22 and the weight 35 due to the pressing force of the spring 23 and gravity is stopped. In this stopped state, a space S is provided below the weight 35 and above the projecting end 34 of the projecting portion 33 for placing the cotter 8 in advance on the jig before assembly (see FIG. 4). Further, the lower end portion or the distal end portion of the shaft portion 29 of the piston member 22 protrudes from the main body 21. A shaft portion 29 exists on the radially inner side of the projecting end 34 of the projecting portion 33, that is, the shaft portion 29 faces the projecting end 34 in the radial direction.

  The shaft portion 29 has a constant outer diameter d1 over its entire length, and in particular, the outer diameter d1 is larger than the outer diameter d2 of the valve stem 7 (see FIG. 3). The hole diameter D2 of the stem hole 30 is substantially the same as the outer diameter d2 of the valve stem 7. Further, the inner diameter D1 of the projecting end 34 in the main body 21 is larger than the outer diameter d1 of the shaft portion 29 of the piston member 22, and therefore, a radius of (D1-d1) / 2 is provided between the projecting end 34 and the shaft portion 29. A gap 36 having a directional distance is formed. As will be described in detail later, the gap 36 has such a size that the cotter 8 cannot pass therethrough. Further, the inner diameter D1 of the protruding end 34 of the main body 21 is set to be equal to or smaller than the upper end inner diameter D3 (see FIG. 3) of the center hole 9A of the retainer 9. The reason for this will also be described later.

  A pull-in member 37 is attached to the piston member 22 for pulling up the piston member 22 from the outside against the force of the spring 23 and thereby pulling the shaft portion 29 into the main body 21. The retracting member 37 is a stay that is attached to the upper end portion of the piston member 22 and extends upward. The stay is inserted through a hole 38 provided in the lid plate 24, and the upper end portion located outside the main body 21 is fingered. It is bent so that it can be hooked.

  Next, a method for assembling the cotter 8 using the cotter assembling jig 20 and a method for assembling the valve operating mechanism will be described.

  First, referring to FIG. 2, the intake valve 2 is inserted into the guide pipe 5 on the cylinder head 1 side from below, and the intake valve 2 is restrained so that the intake valve 2 does not move relative to the cylinder head 1 at least downward. To do. This is realized, for example, by placing the cylinder head 1 with the intake valve 2 in the inserted state on the work table T. That is, by placing the cylinder head 1 on the work table T, the intake valve 2 is also placed on the work table T, and the lowering of the intake valve 2 relative to the cylinder head 1 is prevented. Next, the valve spring 3 is temporarily placed around the outer periphery of the valve stem 7, and the retainer 9 is temporarily placed on the upper end surface of the valve spring 3 while the valve stem 7 is inserted.

  On the other hand, on the jig side, referring to FIG. 1, the retracting member 37 is pulled from the outside so that the lower end of the shaft portion 29 of the piston member 22 is positioned slightly above the protruding end 34 of the main body 21, and in this state For example, the cotter 8 is arranged around the lower end portion of the shaft portion 29 using tweezers. When the jig is placed in a vertical state as shown in the drawing, the weight 35 slides down along the shaft portion 29 and the cotter 8 is sandwiched between the protruding portion 33 and the jig 35. As a result, the cotter 8 is temporarily held (see FIG. 4). Next, when the pulling force of the stay 37 is released, the piston member 22 and the shaft portion 29 are pushed down by the force of the spring 23, and the descent stops when the piston member 22 hits the weight 35. At this time, the setting of the cotter 8 on the jig as the previous work is completed. At this time, the lower end portion of the shaft portion 29 protrudes slightly downward from the main body 21.

  Next, referring to FIGS. 1 and 4, first, the stem hole 30 at the lower end portion of the shaft portion 29 is fitted into the upper end portion of the valve stem 7. As a result, the jig is aligned with the valve stem 7 to prevent the jig from being tilted or shaken. Then, while pressing the contact surface 32 of the stem hole 30 against the upper end surface of the valve stem 7, a downward pressing force Fd is applied to the main body 21 (for example, the cover plate 24), and the main body 21 is pressed down against the force of the spring 23. Then, the piston member 22 and the shaft portion 29 move upward against the main body 21 against the force of the spring 23, and the shaft portion 29 is drawn into the main body 21. Thereafter, the retainer hole 26 of the jig is fitted into the retainer 9, and the contact surface 28 of the retainer hole 26 contacts the upper surface of the retainer 9. Since the jig has already been centered with respect to the valve stem 7, the retainer 9 is also accurately centered with respect to the valve stem 7 when the retainer 9 is fitted, particularly at the time of subsequent contact. Become. Thereby, also in the subsequent work, the cotter gap 40 between the retainer 9 and the valve stem 7 is kept uniform over the entire circumference, and the inclination of the retainer 9 with respect to the valve stem 7 is prevented.

  When the main body 21 is further pushed down, the retainer 9 gradually compresses the valve spring 3, and the retainer 9 is lowered with respect to the valve stem 7. 1 and 5, when the position of the cotter gap 40 is positioned below (preferably slightly below) the position after the assembly of the cotter, a radius is formed at the protruding end 34 of the protruding portion 33. A member opposed in the direction changes from the shaft portion 29 to the valve stem 7. As a result, the gap 36 is enlarged, and the cotter 8 held so far is dropped and supplied to the cotter gap 40. Since the cotter gap 40 is kept uniform all around as described above, the cotter 8 after dropping is also properly arranged in the cotter gap 40.

  In other words, the timing when the cotter 8 falls is the timing when the protrusion 11 of the cotter 8 dropped and supplied to the cotter gap 40 is positioned at least below the cotter groove 10 of the valve stem 7. Preferably, the timing is such that the protrusion 11 is positioned slightly below the cotter groove 10, thereby minimizing the subsequent distance of the cotter 8 and minimizing the drag of the cotter 8 to the valve stem 7. It can be stopped to the limit. In the cotter assembling jig of the present embodiment, at least the axial position of the protruding end 34 of the protruding portion 33 is set so that the cotter 8 is dropped at such timing.

  Since the weight 35 always applies a downward force to the cotter 8 before dropping, the cotter 8 can be reliably dropped simultaneously with the expansion of the gap 36. For example, even when the cotter 8 is wet with oil, the cotter 8 can be reliably peeled off from the adhesion by the oil, and the cotter 8 can be dropped.

  Here, the gap 36 when the shaft portion 29 faces the projecting end 34 of the projecting portion 33 has a size (distance in the radial direction) of (D1−d1) / 2, and the projecting end of the projecting portion 33. The gap 36 when the valve stem 7 faces 34 has a size of (D1-d2) / 2. The size of the former gap 36 is such that the cotter 8 cannot pass through, while the size of the latter gap 36 is such that the cotter 8 can pass through. That is, at least the inner diameter D1 of the protruding end 34 is set so as to establish such a relationship.

  Next, referring to FIGS. 1 and 6, when the pressing force Fd to the main body 21 is weakened or released, the shaft portion 29 is continuously pressed against the valve stem 7 by the spring 23, but the main body 21 and thus the retainer 9 is It rises in a concentric state with 7. Accordingly, the retainer 9 and the cotter 8 are raised while the cotter 8 is properly held in the cotter gap 40. When the protrusion 11 of the cotter 8 is fitted into the cotter groove 10, the cotter 8 is hugged to the valve stem 7, and at the same time, the retainer 9 is fitted into the cotter 8, and the cotter assembling work and the valve operating mechanism assembling work are completed.

  Thus, according to the cotter assembling jig of the present embodiment, the cotter 8 can be dropped and supplied to the gap 40 between the retainer 9 and the valve stem 7. Therefore, there is no operation for forcibly fitting the cotter 8 into the valve stem 7, and the distance that the cotter 8 slides relative to the valve stem 7 is increased so that the supplied cotter 8 is raised and fitted into the cotter groove 10. It can be suppressed to a slight distance until the whole. Thereby, damage to the cotter 8 and the valve stem 7 can be minimized. In addition, since the retainer 9 is aligned with the valve stem 7 when the retainer 9 is lowered and raised, the gap 40 and the cotter 8 between the retainer 9 and the valve stem 7 are maintained even when the retainer 9 and the cotter 8 are slightly raised. Thus, the cotter 8 and the valve stem 7 can be prevented from being damaged without forcibly dragging the cotter 8.

  Further, the cotter 8 can be dropped and supplied at the appropriate timing as described above, the sliding of the cotter 8 with respect to the valve stem 7 can be minimized, and the cotter 8 and the valve stem 7 can be prevented from being damaged. .

  According to the cotter assembling jig of this embodiment, once the cotter 8 is set on the jig, the cotter 8 is automatically moved by one action of fitting, pushing and releasing (pulling back) into the valve stem 7. Can be assembled. Therefore, the operation is very simple. In addition, the structure is simple and small, and it can be widely used not only in engine production factories but also in maintenance factories. Although the cotter assembling jig of this embodiment can be manually operated, for example, it can be used as a part of an automatic engine assembly apparatus and can be operated automatically.

  According to the cotter assembling jig of the present embodiment, the minimum inner diameter D1 at the protruding end 34 of the protruding portion 33 is set to be equal to or smaller than the inner diameter D3 of the upper end of the center hole 9A of the retainer 9 (D1 ≦ D3). Thus, the dropped cotter 8 can be accurately dropped into the gap 40 between the retainer 9 and the valve stem 7 without hitting the upper surface of the retainer 9.

  Various other embodiments of the present invention are conceivable. For example, the valve stem may be a valve stem of an exhaust valve. Further, for example, when the cotter itself is sufficiently heavy to peel off the adhesive force of the oil, or when the oil is not used, the weight can be omitted. The shape, dimensions, and the like of each part can be appropriately changed within a range in which the above-described effects can be exhibited.

  The embodiment of the present invention is not limited to the above-described embodiment, and includes all modifications, applications, and equivalents included in the concept of the present invention defined by the claims. Therefore, the present invention should not be construed as being limited, and can be applied to any other technique belonging to the scope of the idea of the present invention.

It is a longitudinal cross-sectional view which shows the cotter assembly | attachment jig | tool which concerns on embodiment of this invention. It is a longitudinal cross-sectional view which shows the valve operating mechanism of the engine in which a cotter is assembled | attached. It is a longitudinal cross-sectional view which shows the valve stem in an assembly state, a retainer, a cotter, and a valve spring. It is a longitudinal cross-sectional view for demonstrating the usage method of the cotter assembling jig | tool of this embodiment, and the state which the jig | tool centered on the valve stem is shown. It is a longitudinal cross-sectional view for demonstrating the usage method of the cotter assembly jig | tool of this embodiment, and shows the state by which the cotter was fall-supplied. It is a longitudinal cross-sectional view for demonstrating the usage method of the cotter assembly jig | tool of this embodiment, and shows the state after a cotter assembly.

Explanation of symbols

3 valve spring 7 valve stem 8 cotter 9 retainer 9A center hole 10 cotter groove 11 projection 20 cotter assembly jig 21 body 22 piston member 23 spring 26 retainer hole 29 shaft portion 30 cotter hole 33 protrusion 35 weight 36 clearance 40 cotter clearance D1 Minimum inner diameter of protruding part D3 Inner diameter of upper end of retainer center hole d1 Outer diameter of shaft part d2 Outer diameter of valve stem

Claims (8)

A cotter assembling jig for assembling a cotter into a gap between the valve stem and the retainer by pressing down a retainer while compressing a valve spring arranged on the outer peripheral side of a valve stem of an internal combustion engine,
A cylindrical body arranged in alignment above the valve stem for engaging and pushing down the retainer;
A piston member movably inserted into the body;
A shaft portion that extends downward from the piston member and fits the upper end portion of the valve stem at the lower end portion;
A biasing member disposed in the main body and biasing the piston member downward;
A protrusion provided on the inner wall of the main body at a position below the piston member and capable of facing the shaft portion or the valve stem with a predetermined gap in the radial direction according to the position of the piston member with respect to the main body. And
When the protruding portion faces the shaft portion, the cotter is held so that the cotter does not fall from the gap between the protruding portion and the shaft portion, and when the protruding portion faces the valve stem, the protruding portion A cotter assembling jig configured to drop the cotter through the gap between the valve stem and the valve stem and supply the cotter to the gap between the valve stem and the retainer.   The protrusion and the valve stem face each other at a timing such that the protrusion of the cotter supplied to the gap between the valve stem and the retainer is positioned at least below the cotter groove of the valve stem, and the cotter The cotter assembling jig according to claim 1, wherein the cotter assembling jig is configured to fall.   The cotter set according to claim 1, further comprising a weight that is movably provided below the piston member in the main body and presses the cotter held in the main body downward by its own weight. Attached jig.   The cotter assembling jig according to any one of claims 1 to 3, wherein a minimum inner diameter of the protruding portion is equal to or smaller than an upper end inner diameter of a center hole of the retainer.   The cotter assembling jig according to any one of claims 1 to 4, wherein the protruding portion has a tapered shape that gradually reduces the inner diameter as it goes downward.   The cotter assembling jig according to any one of claims 1 to 5, wherein when the lower end portion of the shaft portion is fitted to the upper end portion of the valve stem, the shaft stem is aligned with the valve stem.   The cotter assembling jig according to any one of claims 1 to 6, wherein the main body is fitted to the retainer after the lower end portion of the shaft portion is fitted to the upper end portion of the valve stem. The cotter assembling jig according to claim 1, wherein the shaft portion has a larger diameter than the valve stem.

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