JPH01177402A - Coupling method and coupling jig for rocker arm - Google Patents

Abstract

PURPOSE:To make each rocker arm into a unit so as to make coupling easy by inserting a single dummy shaft which can be extracted by means of a rocker shaft in plural rocker arms while detachably connecting each driving rocker arm with each other by means of a coupling jig. CONSTITUTION:The first and the second driving rocker arms 7, 8, which are respectively connected with an intake valve and an exhaust valve, and a free rocker arm 9, which is provided between the first and the second rocker arms and attaches/detaches the rocker arms to/from each other are respectively coupled with a common rocker shaft. A single dummy shaft 45, which can be extruded by the rocker shaft, is inserted in each of rocker arms 7-9. Each of driving rocker arms 7, 8 is detachably connected with each other by a coupling jig 46. Thereby, after each of rocker arms 7-9 is made into a unit, it is coupled with the rocker shaft. In this case, each of notches 47, 48, etc., with which each tappet screw 16 of each of driving rocker arms 7, 8 is engaged, is provided to the coupling jig 46.

Description

Detailed Description of the Invention A1 Object of the Invention (1) Industrial Field of Application The present invention relates to first and second drive rocker arms that are interlocked and connected to an intake valve or an exhaust valve; The present invention relates to a rocker arm assembling method for assembling a free rocker arm disposed between front drive rocker arms onto a common rocker shaft, and an assembling jig used during the assembling.

(2) Prior Art Conventionally, such three rocker arms are assembled to a common rocker shaft, for example, in Japanese Patent Application Laid-Open No. 61-19911.
As is known from Japanese Patent Publication No. 2003-12000, the assembly is sometimes carried out by assembling each rocker arm individually to the rocker shaft.

(3) Problems to be Solved by the Invention However, if each rocker arm is individually assembled to the rocker arm as in the above-mentioned conventional method, the assembly work is time consuming and maintenance work is also complicated. was.

The present invention has been made in view of the above circumstances, and provides a method for assembling a rocker arm that can efficiently attach each rocker arm to a rocker shaft, and an assembling jig used in the method. The purpose is to

B0 Structure of the Invention (1) Means for Solving Problems According to the method of the present invention, a single dummy shaft that can be pushed out by a rocker shaft is inserted into each rocker arm, and an assembly jig is used to insert the first and second dummy shafts into each rocker arm. The drive rocker arms are removably connected to form each rocker arm into a unit, and each rocker arm is assembled to the rocker shaft in the unit state.

Further, the assembly jig according to the present invention has first and second notches on one side into which the tappet screws of the first and second drive rocker arms can be fitted, and each locking nut and the first and second drive rocker arms. It is formed into a flat plate shape to be held between the rocker arm and the rocker arm.

(2) Effect In the method of the present invention described above, the first and second drive rocker arms and the free rocker arm between the front drive rocker arms are made into a unit by a dummy shaft and an assembly jig, and the unit is attached to the rocker shaft while remaining in the unit state. This makes it possible to assemble the parts, thereby simplifying the assembling work and improving work efficiency.

Furthermore, the assembly jig according to the present invention enables the front drive rocker arms to be connected by tightening the locking nuts on the first and second drive rocker arms, and each rocker arm is connected with the free rocker arm sandwiched between the front drive rocker arms. can be made into a unit, and the connected state of the first and second drive rocker arms can be easily released by loosening the locking nut.

(3) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, in FIGS. 1, 2, and 3, a pair of intake valves 1a provided in the engine body E are shown.

1b is a low-speed cam 3.3 and a high-speed cam 5 that are integrally provided on a camshaft 2 that is rotationally driven from the engine's crankshaft at a reduction ratio of 1/2, and a rocker shaft 6 that is parallel to the camshaft 2. The first and second drive rocker arms 7.8 and the free rocker arm 9, which are pivotally supported by the rocker arms 7.8, and the free rocker arm 9, and the connection switching mechanism IO provided between the rocker arms 7-9 are operated to open and close.

The camshaft 2 is rotatably disposed above the engine body E, and the low-speed cams 3, 3 are integrated with the camshaft 2 at positions corresponding to the respective intake valves 1a, lb, and the high-speed cams 5 is integrated into the camshaft 2 between the low-speed cams 3 and 3. Each low-speed cam 3.3 has a high portion 3a with a relatively small amount of protrusion along the radial direction of the camshaft 2, and a base interior 3b. The high-speed cam 5 has a radially outward protrusion of the camshaft 2 that is larger than the high portion 3a, and a high portion 5a that extends over a wider central angle range than the high portion 3a, and a base interior 5b. has.

The rocker shaft 6 is fixedly arranged below the camshaft 2. 20 The rocker shaft 6 includes a first drive rocker arm 7 that is interlocked and connected to one intake valve 1a, a second drive rocker arm 8 that is interlocked and connected to the other intake valve 1b, and first and second drive rocker arms 7 that are interlocked and connected to the other intake valve 1b. Free rocker arms 9 arranged between the drive rocker arms 7, 8 are each pivoted adjacent to one another.

One low-speed cam 3 is mounted on the top of the first drive rocker arm 7.
A cam slipper 11 is provided on the top of the second drive rocker arm 8 to slide on the other low-speed cam 3, and a cam slipper 12 on the top of the free rocker arm 9 is provided on the top of the free rocker arm 9 to slide on the high-speed cam 5. Slippers 13 are provided.

On the other hand, a flange 14 is provided at the upper part of both the intake valves 1a, lb, and a valve spring 15 is interposed between the flange 14 and the engine body E.
lb is biased by the valve spring 15 in the valve closing direction, that is, upward. Additionally, tappet screws 16 that abut the upper ends of the intake valves 1a, lb are screwed into the tips of the first and second drive rocker arms 7.8 so as to be movable forward and backward. A locking nut 17, which can rest on the upper side of the rocker arm 7.8, is each screwed on.

The free rocker arm 9 slightly extends from the rocker shaft 6 toward both intake valves 1a and lb, and the free rocker arm 9 is connected to the high-speed cam 5 by a lost motion mechanism 18 interposed between the rocker shaft 6 and the engine body E. It is elastically biased in the direction of sliding contact.

The lost motion mechanism 18 includes a bottomed cylindrical guide member 1 that is fitted into the engine body E with its closed end facing the engine body E.
9, a piston 20 that is slidably fitted into the guide member 19 and has a tapered abutting portion 20a that abuts the free rocker arm 9 at the end on the free rocker arm 9 side; A retaining ring 21 is fitted on the inner surface of the guide member 19 near the opening end, and the piston 20
A first member interposed between the piston 20 and the guide member 19 to urge the free rocker arm 9 into contact with the free rocker arm 9.
and second springs 22 and 23.

A hole 24 is drilled in the engine body E for bottomed installation.
For its installation, the guide member 19 is fitted into the hole 24. A spring chamber 25 is defined between the piston 20 and the guide member 19, and a first spring 22 with a relatively small spring constant is provided between the retainer 26 housed in the spring chamber 25 and the piston 20. is compressed, and the retainer 26 and the guide member 19
A second spring 23 with a relatively large spring constant is installed between the closed end and the closed end.

A small diameter hole 20b with a bottom is coaxially bored in the inner surface of the closed end of the piston 20, and the first spring 22 having a relatively small spring constant is accommodated in the small diameter hole 20b, thereby preventing the first spring 22 from collapsing. is prevented. Also, the contact portion 2 of the piston 20
In order to prevent the inside of the spring chamber 25 from being pressurized or depressurized during the sliding movement of the piston 20, the spring chamber 2
An air vent hole 27 communicating with the outside of the contact portion 20a is formed in the shape of a cross and opens on the outer surface of the contact portion 20a.

The retaining ring 21 can be held at the base end of the abutting portion 20a of the piston 20, thereby preventing the piston 20 from being pulled out from the guide member 19.

In FIG. 4, a connection switching mechanism 10 is provided between each of the rocker arms 7 to 9 for switching between connection and disconnection. This connection switching mechanism 10 includes a first switching pin 28 that can connect the first driving rocker arm 7 and the free rocker arm 9, a second switching pin 729 that can connect the free rocker arm 9 and the second driving rocker arm 8, and a second switching pin 729 that can connect the first driving rocker arm 7 and the free rocker arm 9. It includes a regulation pin 30 that regulates the movement of the first and second switching bins 28 and 29, and a return spring 31 that biases each pin 28 to 30 toward the disconnection side.

The first drive rocker arm 7 has a first guide hole 32 with a bottom that is open to the free rocker arm 9 side and is bored parallel to the rocker shaft 6, and the first switching pin 2B slides into the first guide hole 32. They are movably fitted, and a hydraulic chamber 33 is defined between one end of the first switching pin 28 and the closed end of the first guide hole 32 .

Moreover, the first switching pin 28 is located at the closed end of the first guide hole 32.
A regulating protrusion 34 is provided in a protruding manner to regulate movement toward one end. Furthermore, a communication passage 35 communicating with the hydraulic chamber 33 is provided in the first drive rocker arm 7, and a hydraulic pressure supply passage 36 communicating with a hydraulic pressure supply source (not shown) is provided in the rocker shaft 6.
This hydraulic pressure supply path 36 always communicates with the communication path 34 regardless of the swinging state of the first drive rocker arm 7.

In the free rocker arm 9, a guide hole 37 corresponding to the first guide hole 32 is bored parallel to the rocker shaft 6 and extends between both sides, and one end is in contact with the other end of the first switching pin 28. The second switching bin 29 is connected to the guide hole 37.
is slidably fitted to.

In the second drive rocker arm 8, a second guide hole 38 with a bottom corresponding to the guide hole 37 is opened to the free rocker arm 9 side and is bored parallel to the rocker shaft 6. A bottomed cylindrical regulation bottle 30 that abuts the other end is slidably fitted into the second guide hole 38 . This regulation bottle 30 is arranged with its open end facing the closed end side of the second guide hole 38 , and the flange 30 a that protrudes radially outward at the open end is aligned with the second guide hole 38 . sliding into contact with. The return spring 31 is compressed between the closed end of the second guide hole 38 and the closed end of the regulation bottle 30, and the spring force of the return spring 31 causes the pins 2B, 29.30 that are in contact with each other to It is urged toward the hydraulic chamber 33 side. Moreover, a communication hole 39 for removing air and oil is bored at the closed end of the second guide hole 38.

Further, a retaining ring 40 that can be engaged with the flange 30a of the regulation bottle 30 is fitted into the inner surface of the second guide hole 38. Exposure is prevented.

Moreover, the fitting position of the retaining ring 40 is such that the restriction pin 30 is moved further toward the free rocker arm 9 from the state in which it is in contact with the second switching pin 29 at a position corresponding to between the free rocker arm 9 and the second drive rocker arm 8. is set to prevent

The free rocker arm 9 is provided with recesses 41 and 42, respectively, on the sides facing the first and second drive rocker arms 7.8 by cutting out the weight for weight reduction.
Recesses 41, 4 in the first and second drive rocker arms 7.8
Spring pins 43 and 44, which enter into the recesses 41 and 42, are press-fitted and fixed on the side surface facing 2. These recesses 41.42 and spring pins 43, 44 restrict the amount of relative rocking between the free rocker arm 9 and the first and second drive rocker arms 7.8, but the low speed cam 3.
3. first and second drive rocker arms 7.
8 and high speed cam 5! Contact free rocker arm 9
The recesses 41, 42 have a size that does not impede the relative rocking of the first and second drive rocker arms 7.8 and the free rocker arm 9 during operation. is formed.

By the way, when assembling each of the rocker arms 7.8.9 to the rocker shaft 6, a dummy shaft 45 and an assembling jig 46 are prepared as shown in FIG. The dummy shaft 45 is formed into a cylindrical shape so as to be inserted into each of the rocker arms 7 to 9 instead of the rocker shaft 6. Moreover, the outer diameter of the dummy shaft 45 is set to such an extent that when the rocker shaft 6 is inserted into each of the rocker arms 7 to 9, it is pushed by the end of the rocker shaft 6 and easily detached from each of the rocker arms 7 to 9. Ru.

Referring also to FIG. 6, the assembly jig 46 includes tappet screws 16, 16 of the first and second drive rocker arms 7.8.
It has a flat plate shape to be sandwiched between each locking nut 17.17 and the first and second drive rocker arms 7.8. is formed. Furthermore, on the other side of the assembly jig 46, an abbreviated finger hook 49 is provided on the other side of the assembly jig 46 in a plane perpendicular to the axis of the tappet screw 16°16 engaged with each notch 47, 48.
is bent upward and integrally provided.

Next, to explain the operation of this embodiment, when assembling each of the rocker arms 7 to 9 to the rocker shaft 6, each rocker arm 7 is
- 9 are prepared as a unit, that is, a dummy shaft 45 is inserted into each rocker arm 7 - 9, and the first and second tappet screws 16° 16 of the first and second drive rocker arms 7. Fix the assembly jig 46 by fitting the openings 47 and 48 with the nut 17°17.
and the first and second drive rocker arms 7.8 by tightening the locking nut 17.17.
and the second drive rocker arm 7° 8 are connected by the assembly jig 46 (at this time, each component that constitutes the connection switching mechanism 10, namely the first switching pin 28, the second switching pin 29, the regulating pin 30, The return spring 31 etc. is attached to each rocker arm 7 to 9.
It is incorporated into the corresponding part of.

Each rocker arm 7 to 9 in a unitized state like this
When the rocker shaft 6 is inserted into the dummy shaft 45
is pressed by the end of the rocker shaft 6 and extracted from each rocker arm 7-9.

This allows each rocker arm 7 to 9 to be assembled to the rocker shaft 6, and thus each rocker arm 7 to 9
0, which makes it possible to assemble easily and efficiently.
The assembly jig 46 is removed by loosening each locking nut 17.17 when adjusting the tappet clearance by adjusting the forward and backward positions of the tappet screws 16,16. That is, when the lock nut 17.17 is loosened, the finger hook 49 can be hooked with a finger and the assembly jig 46 can be removed from the first and second drive rocker arms 7.8 by pulling the assembly jig 46. Can be done.

Next, the operation after the rocker arms 7 to 9 have been assembled to the rocker shaft 6 will be described. When the engine is operating at low speed, the hydraulic pressure in the hydraulic chamber 33 is released in the connection switching mechanism 10, and each pin 28 to 3 is in a disconnected state in which it has moved to the maximum extent towards the hydraulic chamber 33 due to the spring force of the return spring 31. In this state, the first and second switching bins 28, 29
The abutting surfaces of the second switching pin 29 and the regulating pin 300 are located at positions corresponding to between the first driving rocker arm 7 and the free rocker arm 9, and the contact surfaces of the second switching pin 29 and the regulating pin 300 are located at positions corresponding between the free rocker arm 9 and the second driving rocker arm 8. be. Therefore, each rocker arm 7-9 is in a state in which relative angular displacement is possible with respect to each other.

In such a disconnected state, the first and second drive rocker arms 7.8 swing in response to sliding contact with the low-speed cam 3.3 due to the rotational operation of the camshaft 2, and therefore both intake valves 1a, Ib opens and closes at a timing and lift amount depending on the shape of the low-speed cams 3, 3. At this time, the free rocker arm 9 swings in response to sliding contact with the high-speed cam 5, but the swinging action does not have any influence on the first and second drive rocker arms 7.8.

High hydraulic pressure is supplied to the hydraulic chamber 33 when the engine is operating at high speed. As a result, the first and second switching bins 28, 29 and the regulation bin 30 move toward the connection position against the spring force of the return spring 31, and the first switching bin 28 fits into the guide hole 37 and The two switching pins 29 fit into the second guide holes 38, and the rocker arms 7 to 9 are connected. At this time, the swing amount of the free rocker arm 9 that is in sliding contact with the high-speed cam 5 is the largest, so the first and second drive rocker arms 7.8 swing together with the free rocker arm 9, and both intake valves 1a and lb are operated for high-speed use. The opening and closing operations are performed at timing and lift amount depending on the shape of the cam 5.

During this connection operation, the axes of the first guide hole 32, guide hole 37, and second guide hole 38 may not completely coincide with each other due to manufacturing tolerances of the rocker arms 7 to 9. However, when the free rocker arm 9 is in sliding contact with the base interior 5b of the high-speed cam 5, the second spring 23 in the lost motion mechanism 18 is in a free length state, and the piston 20
There is a gap between the retainer 26 and the retainer 26. Therefore, it is possible to slightly swing the free rocker arm 9 while contracting the first spring 22 whose spring constant is set to be relatively small, and to slightly push down the free rocker arm 9 with the tip of the first switching pin 28. , and push up to align the axes perfectly.

Furthermore, during the above-mentioned high-speed operation, since both intake valves 1a and lb are driven to open and close by the free rocker arm 9, it is necessary to ensure that the cam slipper 13 of the free rocker arm 9 slides into contact with the high-speed cam 5, and a lost motion mechanism is required. 18 is required to press the free rocker arm 9 toward the camshaft 2 with a relatively strong spring force. When the high portion 5a of the high-speed cam 5 comes into sliding contact with the cam slipper 13, the first spring 22 whose spring constant is relatively small is pressed against the piston 20.
The piston 20 is compressed until it contacts the retainer 26, and the piston 20 is urged toward the high-speed cam 5 by the second spring 23 having a relatively large spring constant. Therefore, the free rocker arm 9 is in sliding contact with the high-speed cam 5 with a relatively large spring force, and a high lift load can be obtained.

Moreover, the lost motion mechanism 18 sequentially inserts the second spring 23, retainer 26, first spring 22, and piston 20 into the guide member 19, and attaches the retaining ring 21 to the guide member 19.
9, the unitized lost motion mechanism 18 can be assembled into the engine body E by simply fitting it into the hole 24. can make your work much easier. Furthermore, since the contact portion 20a of the piston 20 in the lost motion mechanism 18 is formed in a tapered shape, the lost motion run mechanism 18 can be disposed close to the pivot portion of the free rocker arm 9 to the rocker shaft 6. It becomes possible to reduce the inertia weight of the free rocker arm 9, thereby reducing the driving force. Moreover, by forming the air vent hole 27 in a cross shape, the weight of the piston 20 can be reduced.
This also allows the inertia weight to be reduced.

Furthermore, in the connection switching mechanism 10, the retaining ring 40 that can be secured to the regulation pin 30 is fitted into the inner surface of the second guide hole 38, so that when the connection switching mechanism 10 is maintained, the regulation pin 30
Even if the pressing force is released, the return spring 31 reliably prevents the regulating pin 30 from popping out from the second guide hole 38.

Moreover, the relative rocking of the free rocker arm 9 and the first and second drive rocker arms 7.8 is caused by the spring pin 43.
44 is restricted within a movable range within the recesses 41 and 42, each rocker arm 7 to 9 is thick (relative rocking is prevented during maintenance, etc.) Parts incorporated in each rocker arm 7.9, such as the first switching pin 28 and the second switching pin 29, can be prevented from falling off.
This prevents them from being accidentally installed after falling off.

In the above embodiments, the valve operating system for the intake valves 1a and 1b has been described, but the present invention is also applicable to the valve operating system for the exhaust valves.

C0 Effects of the Invention As described above, according to the method of the present invention, a single dummy shaft that can be pushed out by the rocker shaft is inserted into each rocker arm when the rocker shaft is inserted, and the first and second drives are connected by the assembly jig. The rocker arms are removably connected to form each rocker arm into a unit, and each rocker arm is assembled to the rocker shaft in the unit state, so the work of forming each rocker arm into a unit and assembling becomes extremely easy. , assembly work efficiency can be improved.

Further, the assembly jig according to the present invention has first and second notches on one side into which the tappet screws of the first and second drive rocker arms can be fitted, and each locking nut and the first and second drive rocker arms. Since it is formed into a flat plate shape to be sandwiched between the rocker arm and the rocker arm, the first and second drive rocker arms can be easily connected to form a unit of each rocker arm, and the method of the present invention can be carried out appropriately. Can be done.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a plan view, FIG. 2 is a sectional view taken along the line ■-■ of FIG. 1, and FIG.
Figure 4 is a cross-sectional view taken along line IV-mV in Figure 2, Figure 5 is a plan view showing the unitized state during assembly, and Figure 6 is a cross-sectional view of the assembly jig. It is an enlarged perspective view. 1a, 1b...Intake valve, 6...Rocker shaft, 7
゜8... Drive rocker arm, 9... Free rocker arm, 16... Tappet neck, 17... Lock nut,
45...Dummy shaft, 46...Assembling jig, 47
．． 48...notch part

Claims (2)

[Claims] (1) The first and second driving rocker arms are interlocked and connected to the intake valve or the exhaust valve, and the first and second driving rocker arms can be connected and disconnected from each other, and are arranged between the two driving rocker arms. In the rocker arm assembly method for assembling the rocker arms onto a common rocker shaft, a single dummy shaft that can be pushed out by the rocker shaft is inserted into each rocker arm, and an assembly jig is used to connect the first and second driving rocker arms. A method for assembling a rocker arm, characterized in that each rocker arm is detachably connected to form a unit, and each rocker arm is assembled to a rocker shaft in the unit state. (2) The first and second tappet screws are respectively screwed together to be interlocked and connected to the intake valve or the exhaust valve, and each tappet screw is screwed with a retaining nut.
In an assembly jig used when assembling a driving rocker arm and a free rocker arm arranged between the first and second rocker arms so as to be switchable between connection and disconnection with the first and second rocker arms to a common rocker shaft, 1
and has first and second notches on one side into which tappet screws of the second drive rocker arm can be fitted, and is shaped like a flat plate to be held between each locking nut and the first and second drive rocker arms. An assembly jig characterized by being formed.