JPH0565812A - Tappet clearance adjusting device for engine - Google Patents

Abstract

PURPOSE:To positively engage a driver and a socket with an adjusting screw and a locknut by floating-supporting the driver and the socket so that they can be freely advanced and retreated, and providing a guide sleeve fitting onto the adjusting screw with aligning function. CONSTITUTION:A driver 15 and a socket 21 are floating-supported respectively so that they can be freely advanced and retreated in the axial direction with respect to a first driving shaft 13 and a second driving shaft 18. A guide sleeve fitting onto an adjusting screw (a1) with aligning function is provided in the socket 21 so that the sleeve sheathes the driver 15. The guide sleeve 22 eliminates misalignment of the adjusting screw (a1) to positively engage the driver 15 and the socket 21 with the adjusting screw (a1) and a locknut (a2) respectively. An adjusting head 4 is oscillated to oscillate a rocker arm (a) through the socket 21 and the guide sleeve 22 to allow the slip face (a3) to abut against a valve cam (c).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention loosens a lock nut for an adjusting screw that is screwed into a rocker arm, and rotates the adjusting screw while the slipper surface of the rocker arm is in contact with a valve cam to provide a tappet clearance. The present invention relates to a tappet clearance adjusting device for an engine to be adjusted.

[0002]

2. Description of the Related Art Conventionally, as an adjusting device of this type, as disclosed in Japanese Patent Publication No. 54-41651, a first drive source for an adjusting screw and a lock nut are provided above an adjusting station for mounting an engine. An adjusting head equipped with a second drive source is provided so as to be movable up and down toward the rocker arm, and a driver engaged with the adjusting screw is connected to the first drive shaft connected to the first drive source, and
The second drive shaft connected to the drive source is formed in a cylindrical shaft shape surrounding the first drive shaft, and the second drive shaft is connected to the socket fitted on the lock nut so that the driver and the socket rotate gently. While lowering the adjusting head, engage the screwdriver with the adjusting screw and the socket with the locknut, loosen the locknut by rotating the socket, and then rotate the screwdriver to tighten and loosen the adjusting screw. It is known to adjust the tappet clearance by performing a sword.

[0003]

Before the adjustment of the tappet clearance, the posture of the rocker arm is not determined due to the variation in the clearance, so that the axis line of the adjusting screw and the axis line of the driver and the socket do not coincide with each other, and the driver or the socket is adjusted. It may not engage properly with the screw or lock nut. Further, when adjusting the tappet clearance, the slipper surface of the rocker arm must be brought into contact with the valve cam, so that it is necessary to separately provide the adjusting device with a pressing means for pressing the slipper surface against the valve cam. The structure becomes complicated. By the way, there are two types of rocker arms, one that adjusts the operating point with the adjusting screw attached to the valve operating point of the arm, and the other that uses the fulcrum adjusting type that installs the adjusting screw at the fulcrum portion of the arm. In this case, the posture of the rocker arm becomes more unstable, and the structure in which the intermediate slipper surface of the rocker arm is brought into contact with the valve cam from below as in the embodiment described later is generally adopted. It becomes difficult to make contact with the valve cam. In view of the above points, the present invention makes it possible to reliably engage the driver and the socket with the adjusting screw and the lock nut of the fulcrum-adjustable rocker arm, and to use a complicated pressing means for the slipper surface of the rocker arm. It is an object of the present invention to provide a device that can be brought into contact with a valve cam without a valve.

[0004]

[Means for Solving the Problems] In order to achieve the above object,
The present invention is a device for adjusting the tappet clearance by loosening a lock nut for an adjusting screw screwed into a rocker arm, and rotating the adjusting screw in a state where a slipper surface of the rocker arm is in contact with a valve operating cam, A first drive source for the adjusting screw and a second drive source for the lock nut are mounted on the adjusting head.
A first drive shaft connected to the drive source is connected to a driver engaged with the adjustment screw, and a second drive shaft connected to the second drive source is formed in a tubular shaft shape surrounding the first drive shaft. In a structure in which a socket externally fitted to a lock nut is connected to the second drive shaft, a driver and a socket are supported in a floating manner so as to be movable back and forth in the axial direction with respect to the first drive shaft and the second drive shaft, respectively. A guide sleeve that is externally fitted to the driver and externally fitted to the adjusting screw with an aligning function, the guide sleeve is fixed to either of the drive shafts, and the adjusting head serves as a rocking fulcrum of the rocker arm. It is characterized in that it can swing about a substantially concentric fulcrum.

[0005]

[Operation] If the axis of the adjusting screw does not match the axis of the driver and the socket, when the adjusting head is advanced to the rocker arm side, the driver and the socket initially interfere with the adjusting screw and the lock nut. Even if such interference occurs, the forward movement of the adjusting head is not restricted by the floating operation with respect to the drive shaft, and the adjusting screw is inserted into the sleeve while being aligned with the forward movement of the guide sleeve. The misalignment is eliminated, and the driver and socket are securely engaged with the adjusting screw and the lock nut, respectively. When the adjusting head is swung after this engagement, the rocker arm is also swung through the socket and the guide sleeve, and the slipper surface of the rocker arm abuts the valve operating cam. In this state, rotation of the socket loosens the lock nut, and rotation of the driver tightens and loosens the adjustment screw to adjust the tappet clearance.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 2, reference numeral a denotes a rocker arm provided on a cylinder head b of an engine, and one end of the rocker arm a is used for adjusting a fulcrum position with a lower end supported by a seat b1 on the cylinder head b. The adjuster screw a1 is screwed into the locker arm a so that the locker arm a can be fixed to the adjuster screw a1 with the lock nut a2, and the slipper surface a3 that abuts the valve cam c on the upper surface of the intermediate portion of the rocker arm a.
Is formed, the rocker arm a is swung by the rotation of the valve cam c with the lower end of the adjusting screw a1 as a fulcrum, and the valve d is opened and closed via the action point part a4 at the other end of the rocker arm a. Therefore, the tappet clearance is adjusted by the adjusting device shown in FIG.

In the adjusting device, an adjusting head 4 equipped with driving means for adjusting screw a1 and lock nut a2 is mounted on a lifting frame 3 provided on a machine frame 1 so as to be lifted by a cylinder 2 by a cylinder 5. Guided by an arcuate guide rail 6 fixed to the lifting frame 3, the rocker arm a is supported so as to be swingable around a fulcrum substantially concentric with the swing fulcrum of the rocker arm a, and is further regulated by a stopper 7 below the machine frame 1. A movable frame 9 that is moved forward and backward by a cylinder 8 is provided at a lower measurement position, and the movable frame 9 has a valve displacement gauge 10 having a probe 10a that abuts on a retainer d1 of the valve d, and an action point portion of a rocker arm a. Measuring element 11 that abuts on the abutment a5 formed on a5
The rocker arm displacement gauge 11 having a is provided. Reference numeral 6a in the drawing denotes a guide roller which is attached to the adjusting head 4 so that the guide rail 6 is sandwiched from above and below.

The drive means for the adjusting screw a1 mounted on the adjusting head 4 comprises a first drive source 12 composed of a servo motor, a first drive shaft 13 extending below the drive source 12, and a rotation stop at the lower end of the drive shaft 13. And a driver 15 floatingly supported so as to be able to move upward against the spring 14, and the drive means for the lock nut a2 is a second drive source 16 composed of a nut runner, and a gear 17 via this. The cylindrical second outer periphery of the first drive shaft 13 to be connected
It is composed of a drive shaft 18 and a socket 21 which is fixed to the lower end of the second drive shaft 18 via a pin 19 and is floatingly supported against a spring 20 so as to be movable upward. A guide sleeve 22 which is externally fitted to the driver 15 and externally fitted to the adjusting screw a1 with an aligning function is provided, and the sleeve 22 is fixed to the first drive shaft 13 or the second drive shaft 14.

When adjusting the tappet clearance,
First, while slowly rotating the driver 15 and the socket 21, the adjustment head 4 is lowered by the movement of the elevating frame 3, the driver 15 is engaged with the groove at the top of the adjusting screw a1, and the socket 21 is externally fitted to the lock nut a2. Engage. At this time, if the axis line of the adjusting screw a1 does not match the axis line of the driver 15 or the socket 21, the driver 15 and the socket 21 interfere with the adjusting screw a1 and the lock nut a2 so that they are not properly engaged. In the present embodiment, the driver 15 and the socket 21 are provided with the spring 14 and the spring 14 with respect to the drive shafts 13 and 18, respectively.
20. On the other hand, the adjusting screw a1 is inserted into the guide sleeve 22 through the tapered hole portion at the lower end of the guide sleeve 22, the misalignment of the adjusting screw a1 is eliminated, and the driver 15 and the socket 21 are adjusted by the adjusting screw a1. The a1 and the lock nut a2 are securely engaged. next,
The lock nut a2 is loosened by the rotation of the socket 21, and the adjusting head 4 is swung clockwise in FIG. According to this, a swinging moment acts on the adjusting screw a1 via the socket 21 and the guide sleeve 22,
The rocker arm a is swung so that the slipper surface a3 thereof comes into contact with the base circle of the valve operating cam c. In this state, the movable frame 9 is lowered to the measurement position, and the probe 10 of the valve displacement gauge 10 is moved.
a is a retainer d1 of the valve d and a rocker arm displacement gauge 1
The measuring element 11a of No. 1 is brought into contact with the seat a5 of the rocker arm a. Next, the adjuster screw a1 is tightened by the rotation of the driver 15, one end of the rocker arm a is pulled up, and the action point part a4 at the other end is lowered. Here, if the amount of upward displacement of one end of the rocker arm a is α, the amount of downward displacement of the action point portion a4 is β, and the amount of downward displacement of the valve d is γ, then β and γ change with respect to α. As shown in FIG.
Then, while measuring γ with the valve displacement meter 10, the adjustment screw a1 is tightened, and when γ reaches the predetermined value A, the tightening is stopped, the rocker arm displacement meter 11 is set to the zero point, and then the driver 15 is rotated in the reverse direction. Then, the adjusting screw a1 is loosened, and the measured value of the rocker arm displacement meter 11 becomes the predetermined value A and the specified value B of the tappet clearance.
When the adjustment target value C obtained by adding is reached, the reverse rotation of the driver 15 is stopped and the lock nut a2 is tightened. According to this, the tappet clearance is accurately adjusted to the specified value B. Next, the swinging urging force of the adjusting head 4 by the cylinder 5 is released to raise the elevating frame 3 and the movable frame 9 to complete the adjusting work.

In the above embodiment, the device for the fulcrum-adjustable rocker arm has been described, but it goes without saying that the present invention can be applied to the adjusting device for the action-point-adjustable rocker arm.

[0011]

As is apparent from the above description, according to the present invention, even if the axis line of the adjusting screw and the axis lines of the driver and the socket do not coincide with each other, the misalignment of the adjusting screw can be eliminated and the driver The socket and the socket can be securely engaged with the adjusting screw and the lock nut, respectively, and the rocker arm slipper surface can be brought into contact with the valve cam without additional pressing means simply by swinging the adjusting head. This has the effect of simplifying the device structure.

[Brief description of drawings]

FIG. 1 is a side view of an example of the device of the present invention.

[Fig. 2] Enlarged view of the main part during adjustment work

FIG. 3 is a diagram showing a displacement amount of a rocker arm and a valve.

[Explanation of symbols]

a rocker arm a1 adjusting screw a2 lock nut 4 adjusting head 5 rocking cylinder 6 rocking guide rail 12 first drive source 13 first drive shaft 15 driver 16 second drive source 18 second drive shaft 21 socket 22 guide sleeve

Claims (1)

[Claims] 1. A device for adjusting a tappet clearance by loosening a lock nut for an adjusting screw, which is screwed into a rocker arm, and rotating the adjusting screw with a slipper surface of the rocker arm being in contact with a valve cam. An adjustment head equipped with a first drive source for the adjusting screw and a second drive source for the lock nut,
A first drive shaft connected to the first drive source is connected to a driver engaged with the adjustment screw, and a second drive shaft connected to the second drive source is formed in a tubular shaft shape surrounding the first drive shaft. Then, in the one in which a socket fitted on a lock nut is connected to the second drive shaft, a driver and a socket are supported in a floating manner so as to be movable back and forth in the axial direction with respect to the first drive shaft and the second drive shaft, respectively. A guide sleeve is provided in the socket, which is externally fitted to the driver and externally fitted to the adjusting screw with an aligning function. The guide sleeve is fixed to either of the drive shafts, and the adjusting head is rocked on the rocker arm. A tappet clearance adjusting device for an engine, which is swingable around a fulcrum that is substantially concentric with the fulcrum.