JPH07109166B2 - Locker arm assembly method and assembly jig - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Field of Industrial Application The present invention relates to first and second drive rocker arms that are interlocked with and connected to an intake valve or an exhaust valve, and first and second drive. TECHNICAL FIELD The present invention relates to a rocker arm assembling method for assembling a rocker arm with a free rocker arm that is arranged between both drive rocker arms and is capable of switching connection and disconnection with a rocker arm, and an assembling jig used during the assembling. .

(2) Conventional Technology Conventionally, a structure in which three rocker arms are mounted on a common rocker shaft is known, for example, from Japanese Patent Application Laid-Open No. 61-19911, but at the time of mounting, each rocker arm is individually mounted. It is assembled 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-described conventional case, it takes a long time for the assembling work, and the work becomes complicated during the maintenance work. Was there.

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

B. Configuration of the Invention (1) Means for Solving the Problems 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, and the first and second assembly jigs are used. The two-drive rocker arms are detachably connected to make each rocker arm into a unit, and each rocker arm is assembled to the rocker shaft in the unit state.

Further, the assembling jig according to the present invention has the first and second cutout portions on one side into which the tappet screws of the first and second drive rocker arms can be fitted, and each lock nut and the first and second drive portions. It is formed in a flat plate shape so as to be sandwiched between the rocker arm and the rocker arm.

(2) Operation In the method of the present invention described above, the first and second drive rocker arms and the free rocker arm between the drive rocker arms are unitized by the dummy shaft and the assembling jig, and the rocker shaft is kept in the unit state. Assembling becomes possible, and therefore, the assembling work can be simplified and the work efficiency can be improved.

Further, the assembling jig according to the present invention makes it possible to connect the drive rocker arms to each other by tightening the lock nuts on the first and second drive rocker arms. It can be unitized, and the connection state of the first and second drive rocker arms can be easily released by loosening the lock nut.

(3) Embodiment Hereinafter, one embodiment of the present invention will be described with reference to the drawings. First, in FIG. 1, FIG. 2 and FIG. 3, the pair of intake valves 1a, 1b provided in the engine body E are Camshaft 2 that is driven to rotate from the crankshaft at 1/2 speed reduction ratio
Low-speed cams 3 and 3 and high-speed cam 5 that are integrally provided in the
And the first and second drive rocker arms 7, 8 pivotally supported by the rocker shaft 6 parallel to the camshaft 2 and the free rocker arm 9 and the connection switching mechanism 10 provided between the rocker arms 7 to 9 for opening and closing. Driven.

The camshaft 2 is rotatably arranged above the engine body E, and the low speed cams 3, 3 are integrated with the camshaft 2 at positions corresponding to the intake valves 1a, 1b, and the high speed cam 5 is provided. Is integrated with the camshaft 2 between the low speed cams 3, 3. Each of the low speed cams 3, 3 has a high portion 3a having a relatively small amount of protrusion along the radial direction of the cam shaft 2 and a base circular portion 3b. Further, the high speed cam 5 has a protrusion amount of the cam shaft 2 outward in the radial direction larger than that of the high portion 3a, and a high portion 5a covering a wider central angle range than the high portion 3a.
And a base circle portion 5b.

The rocker shaft 6 is fixedly arranged below the cam shaft 2. This rocker shaft 6 has one intake valve
A first drive rocker arm 7 linked and linked to 1a, and a second drive rocker arm 8 linked and linked to the other intake valve 1b.
And a free rocker arm 9 arranged between the first and second drive rocker arms 7, 8 are pivoted adjacent to each other.

One of the low speed cams 3 is provided above the first drive rocker arm 7.
Is provided with a cam slipper 11 slidingly contacting the second driving rocker arm 8, and a cam slipper 12 slidingly contacting the other low speed cam 3 is provided above the second drive rocker arm 8, and a cam slidingly contacting the high speed cam 5 above the free rocker arm 9. Slippers 13 are provided.

On the other hand, a flange portion 14 is provided above each of the intake valves 1a, 1b, and a valve spring 15 is interposed between the flange portion 14 and the engine body E, so that each intake valve 1a, The valve springs 15 bias the valve 1b in the valve closing direction, that is, upward. Further, at the tips of the first and second drive rocker arms 7 and 8, tappet screws 16 that come into contact with the upper ends of the intake valves 1a and 1b are provided.
Are respectively screwed so as to be able to move forward and backward, and the tappet screw 16 is screwed with a lock nut 17 capable of abutting on the upper surfaces of the first and second drive rocker arms 7, 8.

The free rocker arm 9 is connected to both intake valves from the rocker shaft 6.
The free rocker arm 9 is slightly extended to the sides 1a and 1b, and is elastically biased in a direction in which the free rocker arm 9 slides on the high speed cam 5 by a lost motion mechanism 18 interposed between the free rocker arm 9 and the engine body E.

The lost motion mechanism 18 has a bottomed cylindrical guide member 19 fitted into the engine body E with its closed end facing the engine body E.
A piston 20 slidably fitted to the guide member 19 and having an abutting portion 20a that abuts the free rocker arm 9 in a tapered shape at the end portion on the free rocker arm 9 side;
Between the piston 20 and the guide member 19 in order to elastically urge the piston 20 in the direction of contacting the free rocker arm 9 with the retaining ring 21 fitted to the inner surface of the guide member 19 near the open end so as to engage with the piston 20. First and second springs 22,23 interposed
With.

A bottomed mounting hole 24 is formed in the engine body E, and the guide member 19 is fitted into the mounting hole 24. A spring chamber 25 is defined between the piston 20 and the guide member 19, and a first spring 22 having a relatively small spring constant is contracted between the retainer 26 housed in the spring chamber 25 and the piston 20. A second spring 23 having a relatively large spring constant is contracted between the retainer 26 and the closed end of the guide member 19.

A bottomed small-diameter hole 20b is coaxially bored on 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, whereby the first spring 22 falls. Is prevented. In addition, the abutment portion 20a of the piston 20 is provided with an air vent hole 27 for communicating the spring chamber 25 to the outside in order to prevent the spring chamber 25 from being pressurized and depressurized when the piston 20 slides. It is formed in a cross shape that opens to the outer surface of the contact portion 20a.

The snap ring 21 is engageable with the base end portion of the abutting portion 20a of the piston 20, whereby the guide member 19 of the piston 20 is engaged.
The escape from is blocked.

In FIG. 4, a connection switching mechanism 10 is provided between the rocker arms 7 to 9 to switch between connection and disconnection thereof. The connection switching mechanism 10 includes a first switching pin 28 that can connect the first drive rocker arm 7 and the free rocker arm 9 and a second switching pin 29 that can connect the free rocker arm 9 and the second drive rocker arm 8. 1 and 2
Restriction pin 30 that restricts the movement of switching pins 28 and 29, and each pin 2
And a return spring 31 for urging 8 to 30 toward the connection release side.

The first drive rocker arm 7 is provided with a bottomed first guide hole 32 opened to the free rocker arm 9 side in parallel with the rocker shaft 6, and the first switching pin 28 is slid into the first guide hole 32. A hydraulic chamber 33 is movably fitted and defined between one end of the first switching pin 28 and the closed end of the first guide hole 32.
Moreover, the closed end of the first guide hole 32 is provided with a restriction projection 34 that restricts the movement of the first switching pin 28 toward one end. Further, the first drive rocker arm 7 has a communication passage communicating with the hydraulic chamber 33.
35, a rocker shaft 6 is provided with a hydraulic pressure supply path 36 communicating with a hydraulic pressure supply source (not shown). The hydraulic pressure supply path 36 is connected to the communication path 34 regardless of the swinging state of the first drive rocker arm 7. Always communicate.

A guide hole 37 corresponding to the first guide hole 32 is formed in the free rocker arm 9 in parallel with the rocker shaft 6 between both side surfaces, and one end of the first switching pin 28 is brought into contact with the other end thereof. The second switching pin 29 is slidably fitted in the guide hole 37.

In the second drive rocker arm 8, a bottomed second guide hole 38 corresponding to the guide hole 37 is opened to the free rocker arm 9 side and is bored in parallel with the rocker shaft 6, and the second switching pin 29 A bottomed cylindrical regulation pin 30 that abuts on the other end is slidably fitted in the second guide hole 38. This regulatory pin 30
Is arranged so that its open end faces the closed end side of the second guide hole 38, and the flange portion 30a that projects outward in the radial direction at the open end is in sliding contact with the second guide hole 38. Return spring 3
1 is contracted between the closed end of the second guide hole 38 and the closed end of the restriction pin 30, and the pins 28, 29, 30 that abut against each other by the spring force of the return spring 31 are hydraulic chambers. 33 side is urged. Moreover, the closed end of the second guide hole 38 is provided with a communication hole 39 for removing air and oil.

Further, on the inner surface of the second guide hole 38, the collar portion 30a of the regulation pin 30 is formed.
A snap ring 40 that can be engaged with is attached to the snap ring 40.
This prevents the restriction pin 30 from coming out of the second guide hole 38. Moreover, the fitting position of the retaining ring 40 is further moved to the free rocker arm 9 side from the state where the restriction pin 30 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 block.

The free rocker arm 9 is provided with recesses 41 and 42 on the side surfaces facing the first and second drive rocker arms 7 and 8 respectively by lightening to reduce the weight. Spring pins 43 and 44, which are inserted into the recesses 41 and 42, are press-fitted and fixed to the side surfaces of the recess 8 facing the recesses 41 and 42. Although the relative rocking amounts of the free rocker arm 9 and the first and second drive rocker arms 7 and 8 are restricted by the recesses 41 and 42 and the spring pins 43 and 44, the first rocker arm 3 and the low speed cams 3 and 3 are in sliding contact with each other. Since the first and second drive rocker arms 7 and 8 and the free rocker arm 9 that is in sliding contact with the high-speed cam 5 oscillate relative to each other in the operating state, the recesses 41 and 42 have the first and second drive rocker arms. It is formed in a size that does not hinder the relative swinging of the free rocker arm 9 and the free rocker arm 9 during the operation.

By the way, when the rocker arms 7, 8 and 9 are assembled to the rocker shaft 6, a dummy shaft 45 and an assembly jig 46 are prepared as shown in FIG. Dummy shaft
45 is each rocker arm 7-9 instead of the rocker shaft 6.
It is formed into a cylindrical shape so that it can be inserted into. Moreover, the outer diameter of the dummy shaft 45 is set such that when the rocker shaft 6 is inserted into the rocker arms 7 to 9, the dummy shaft 45 is pushed by the end portion of the rocker shaft 6 and easily separated from the rocker arms 7 to 9. It

Referring also to FIG. 6, the assembling jig 46 has first and second cutout portions 47, 48 into which the tappet screws 16, 16 of the first and second drive rocker arms 7, 8 can be fitted. It is formed in a flat plate shape so as to be sandwiched between the lock nuts 17 and 17 and the first and second drive rocker arms 7 and 8 while having one side portion.
Moreover, on the other side of the assembling jig 46, a substantially L-shaped finger hook 49 is bent upward in a plane orthogonal to the axis of the tappet screws 16 and 16 engaged with the notches 47 and 48. Are provided integrally.

Next, the operation of this embodiment will be described. When the rocker arms 7 to 9 are assembled to the rocker shaft 6, the rocker arms 7 to 9 are unitized and prepared as shown in FIG. 5 before the assembly. Keep it. That is, the dummy shaft 45 is inserted into each rocker arm 7-9, and the first and second cutouts 47, 48 are fitted to the tappet screws 16, 16 of the first and second drive rocker arms 7, 8. Fix the assembly jig 46 to the lock nuts 17, 17 and the first and second
Insert it between the drive rocker arm 7 and 8 and lock nut 17,
The first and second drive rocker arms 7 and 8 are connected by the assembling jig 46 by tightening 17. At this time, each component of the connection switching mechanism 10, that is, the first switching pin 28 and the second switching pin 28
The switching pin 29, the regulation pin 30, the return spring 31 and the like are incorporated in the corresponding parts of the rocker arms 7-9.

Each rocker arm 7 to 9 in the unitized state as described above
When the rocker shaft 6 is inserted into the rocker shaft 6, the dummy shaft 45 is pressed by the end of the rocker shaft 6 and each rocker arm 7 is pushed.
Extracted from ~ 9. As a result, each rocker arm 7-
9 can be assembled to the rocker shaft 6, so that the rocker arms 7 to 9 can be easily and efficiently assembled. The assembling jig 46 is removed in response to loosening the lock nuts 17, 17 when adjusting the tappet clearance by adjusting the advancing / retreating positions of the tappet screws 16, 16. That is, when loosening the lock nuts 17, 17,
The assembly jig 46 can be detached from the first and second drive rocker arms 7 and 8 by placing a finger on the finger hook portion 49 and pulling the assembly jig 46.

Next, a description will be given of the operation after the assembling of the rocker arms 7-9 to the rocker shaft 6 is completed. When the engine is operating at a low speed, the hydraulic pressure in the hydraulic chamber 33 is released in the connection switching mechanism 10 and the pins 28-30 Is in a connection released state in which the spring force of the return spring 31 has moved to the hydraulic chamber 33 side to the maximum extent. In this state, the contact surfaces of the first and second switching pins 28 and 29 are located at positions corresponding to the first drive rocker arm 7 and the free rocker arm 9, and the contact surfaces of the second switching pin 29 and the regulation pin 30 are Free rocker arm 9 and second drive rocker arm 8
It is located in the corresponding position. Therefore, each rocker arm 7
9 to 9 are in a state where relative angular displacement is possible with respect to each other.

In this uncoupled state, the first and second drive rocker arms 7 and 8 swing due to the rotational operation of the cam shaft 2 in response to the sliding contact with the low speed cams 3 and 3, and therefore the intake valves 1a and 1b opens and closes at a timing and a lift amount according to the shapes of the low speed cams 3,3. At this time, the free rocker arm 9 swings in accordance with the sliding contact with the high speed cam 5, but the swinging motion does not affect the first and second drive rocker arms 7 and 8.

High hydraulic pressure is supplied to the hydraulic chamber 33 during high-speed operation of the engine.
As a result, the first and second switching pins 28 and 29 and the restriction pin 30 move to the connecting position side against the spring force of the return spring 31, so that the first switching pin 28 is fitted into the guide hole 37 and The two switching pins 29 are fitted into the second guide holes 38, and the rocker arms 7 to 9 are connected to each other. At this time, since the swing amount of the free rocker arm 9 that is in sliding contact with the high speed cam 5 is the largest, the first and second drive rocker arms 7 and 8 swing together with the free rocker arm 9, and both intake valves 1a and 1b are for high speed. The opening / closing operation is performed at a timing and a lift amount according to the shape of the cam 5.

At the time of this coupling operation, the first guide hole 32, the guide hole 37, and the second guide hole 38 are produced due to manufacturing tolerances of the rocker arms 7 to 9.
The axes of may not match exactly. However, when the free rocker arm 9 is in sliding contact with the base circle portion 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 and the retainer are in a state of free length.
There is a gap between 26. Therefore, it is possible to slightly swing the free rocker arm 9 while contracting the first spring 22 having a relatively small spring constant, and to push down the free rocker arm 9 slightly by the tip of the first switching pin 28. , You can push it up or the axis line can be perfectly matched.

Further, during the high speed operation, both intake valves 1a and 1b are driven to open and close by the free rocker arm 9, so that the cam slipper 13 of the free rocker arm 9 must be surely brought into sliding contact with the high speed cam 5, and the lost motion mechanism is lost. 18 is required to press the free rocker arm 9 toward the camshaft 2 with a relatively strong spring force. Thus, when the high-order portion 5a of the high-speed cam 5 slides on the cam slipper 13, the first spring 22 having a relatively small spring constant contracts until the piston 20 contacts the retainer 26. 20 is biased toward the high speed cam 5 by a second spring 23 having a relatively large spring constant. Therefore, the free rocker arm 9 comes into 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 is provided in the guide member 19.
Second spring 23, retainer 26, first spring 22 and piston 20
Are sequentially inserted and the retaining ring 21 is fixed to the guide member 19 to form a unit. The unitized lost motion mechanism 18 is simply fitted into the mounting hole 24 to be assembled to the engine body E. Assembling can be completed and the assembling work can be made extremely easy. Further, since the contact portion 20a of the piston 20 in the lost motion mechanism 18 is formed in a tapered shape, the lost motion mechanism 18 can be arranged in the vicinity of the pivotal support portion of the free rocker arm 9 to the rocker shaft 6, and thus the free rocker arm 9 can be freely moved. It is possible to reduce the inertial weight of the rocker arm 9, thereby reducing the driving force. Moreover, the air vent hole
By forming the cross 27 in a cross shape, the weight of the piston 20 can be reduced, which also reduces the inertial weight.

Further, in the connection switching mechanism 10, since the retaining ring 40 engageable with the restriction pin 30 is fitted on the inner surface of the second guide hole 38, the force pressing the restriction pin 30 is released during maintenance of the connection switching mechanism 10. However, the return spring 31 reliably prevents the restriction pin 30 from jumping out of the second guide hole 38.

In addition, the relative rocking of the free rocker arm 9 and the first and second drive rocker arms 7, 8 is restricted within the range in which the spring pins 43, 44 can move within the recesses 41, 42, so during maintenance or the like. The rocker arms 7 to 9 are prevented from swinging relative to each other to a large extent, and accordingly, the components, such as the first switching pin 28 and the second switching pin 29, which are respectively incorporated in the rocker arms 7 and 9 to form the connection switching mechanism 10, are provided. It can be prevented from falling off, so that it will not be erroneously incorporated after falling off.

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

C. Effects of the Invention As described above, according to the method of the present invention, when the rocker shaft is inserted, a single dummy shaft that can be pushed out by the rocker shaft is inserted into each rocker arm, and the first and second assembly jigs are used. Since each rocker arm is unitized by detachably connecting the drive rocker arm and each rocker arm is assembled to the rocker shaft in that unit state, each rocker arm can be unitized to make the assembly work extremely easy. It is possible to improve the assembly work efficiency.

Further, the assembling jig according to the present invention has the first and second cutout portions on one side into which the tappet screws of the first and second drive rocker arms can be fitted, and each lock nut and the first and second drive portions. Since it is formed in a flat plate shape so as to be sandwiched between the rocker arm and the rocker arm, it is possible to easily connect the first and second drive rocker arms to unitize each rocker arm, and to appropriately carry out the method of the present invention. You can

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is a plan view, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIG.
Fig. 3 is a sectional view taken along the line III-III, Fig. 4 is a sectional view taken along the line IV-IV in Fig. 2, Fig. 5 is a plan view showing a unitized state during assembly, and Fig. 6 is a sectional view of the assembly jig. It is an expansion perspective view. 1a, 1b ... Intake valve, 6 ... Rocker shaft, 7,8 ... Drive rocker arm, 9 ... Free rocker arm, 16 ... Tappet screw, 17 ... Lock nut, 45 ... Dummy shaft, 46
…… Assembling jig, 47,48 …… Notch

Claims (2)

[Claims] 1. A first rocker arm and a second rocker arm, which are interlocked with and linked to an intake valve or an exhaust valve, and are arranged between the first and second rocker arms so that connection and disconnection of the rocker arms can be switched. In a method of assembling a rocker arm for assembling a free rocker arm with a common rocker arm, a single dummy shaft that can be pushed out by the rocker shaft is inserted into each rocker arm and the first and second drives are performed by an assembling jig. The rocker arms are detachably connected to each rocker arm as a unit,
A method of assembling a rocker arm, characterized in that each rocker arm is assembled to a rocker shaft in the unit state. 2. A first and a second drive rocker arm, in which tappet screws are respectively screwed to be interlocked with and connected to an intake valve or an exhaust valve, and lock nuts are screwed to the tappet screws, respectively. And an assembling jig used when assembling a free rocker arm arranged between both drive rocker arms by making it possible to switch between connection and disconnection with the second rocker arm on a common rocker shaft, the first and second drive rocker arms being provided. Has a first and a second cutout portion on one side into which the tappet screw can be fitted and is formed in a flat plate shape so as to be sandwiched between each lock nut and the first and second drive rocker arms. A characteristic assembly jig.