JPH0589805U - Rocker arm - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent the rotation of the roller shaft of the roller rocker arm due to the rotational torque and to improve the wear resistance of the roller shaft. A roller 6 is used in a rocker arm in which a roller 6 is used in a contact portion with a cam, and both ends 7b and 7b ′ of a roller shaft 7 supported by a shaft hole 5d of the rocker arm 5 are fixed by caulking 7d and 7d ′. A roller shaft 7 having a supporting center portion 7a having higher hardness than both ends 7b, 7b '.
And a pin 8 press-fitted into each of the pin holes 5g and 7e formed in the shaft hole of the rocker arm and one end of the roller shaft to fix them.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a rocker arm.

[0002]

[Prior Art]

 In a valve train mechanism equipped with a rocker arm type overhead cam, the rocker arm is pivotally supported at its approximate center in a rocker shaft, one end abutting against the cam and the other end abutting against the valve stem head. Accordingly, the valve stem head is pressed against the valve spring to open the valve. As for this rocker arm, as shown in FIGS. 1 and 2, a roller 2 is rotatably supported by one end 1a of a rocker arm 1 by a roller shaft 3 and is rolled on a cam surface to reduce wear. There is a roller rocker arm.

As a method of fixing the roller shaft 3 to the rocker arm 1, the roller shaft 3 is fitted into the shaft hole 1b of the rocker arm 1 as shown in the drawing, and both ends 3a, 3a 'are caulked 3b, 3b'. There is a fixed one. When the roller 2 is supported by the roller shaft 3, the roller shaft 3 is directly inserted into the shaft hole 2a of the roller 2 as shown in the figure, and between the roller shaft 3 and the roller shaft. There is a type in which a needle is inserted in the.

[0004]

[Problems to be solved by the device]

 By the way, there is a problem that the fixing of the roller shaft by the caulking is easy to rotate when receiving the rotating torque. Particularly, in the type in which the roller 2 is directly supported on the roller shaft 3 as shown in the figure, the caulking 3b and 3b 'tend to loosen during long-time operation because the rotational torque applied to the roller shaft 3 is high. When the roller shaft 3 starts to rotate, the caulking 3b and 3b 'do not work and rattling with the rocker arm 1 may occur, which may cause the roller shaft 3 to come off or the rocker arm 1 to be damaged. There is.

Further, the hardness of the roller shaft 3 cannot be made too high in order to secure the crimping property between the rocker arm 1 and the roller shaft 3, and as a result, the roller shaft 3 comes into contact with the shaft hole 2a of the roller 2. There is also a problem that the wear resistance of the surface is low, the looseness between them is large, and the durability is poor. The present invention has been made in view of the above points, and an object thereof is to provide a rocker arm that prevents rotation caused by the rotation torque of the roller shaft and has excellent wear resistance of the contact surface with the roller. To do.

[0006]

[Means for Solving the Problems]

 According to the present invention to achieve the above object, a roller is used in a contact portion with a cam, and both ends of a roller shaft pivotally supported in a shaft hole of the rocker arm are fixed by caulking. A roller shaft having a central portion that pivotally supports a roller has a hardness higher than that of both ends pivotally supported by a shaft hole of a rocker arm, and pins formed in the shaft hole of the rocker arm and one end of the roller shaft. The pin is press-fitted into the hole to fix both of them.

[0007]

[Action]

 Both ends of the roller shaft are fixed to the rocker arm by crimping, and are fixed by pins so as not to rotate. As a result, the roller shaft does not rotate even if it receives rotational torque from the roller. The center of the roller shaft that supports the roller is hardened to a higher degree of hardness than both ends that are supported by the shaft hole of the rocker arm, so it has excellent wear resistance and less wear due to rotation of the roller. ..

[0008]

【Example】

 An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. As shown in FIGS. 3 and 4, the rocker arm 5 has a large-diameter shaft hole 5a formed substantially in the center, and a groove 5c for accommodating the roller 6 is provided at one end 5b. A shaft hole 5d orthogonal to 5c is formed. The opening end of the shaft hole 5d is chamfered 5e and 5e 'over the entire circumference, and the diameter is increased. Further, as will be described later, after the roller shaft 7 is caulked and fixed, pin holes 5g and 7e for driving pins are formed in the end surface 5f of the rocker arm 5 and the roller shaft 7 at right angles to the shaft hole 5d. A valve adjusting screw is screwed to the other end of the rocker arm 5 (not shown).

A roller 6 is housed in a groove 5c at one end 5b of the rocker arm 5 with a slight gap, and a center portion 7a of the roller shaft 7 penetrates a shaft hole 6a of the roller 6 and both ends thereof are 7b and 7b 'are fitted into and axially supported by the shaft holes 5d, respectively. The roller shaft 7 has a hollow pipe shape and is set to have the same length as the width of the one end 5b of the rocker arm 5 so that both ends are flush with both side surfaces of the one end 5b (FIG. 4). I am

The roller shaft 7 supports both ends of the roller 6, that is, the hardness of the central portion 7a that is in sliding contact with the inner surface of the shaft hole 6a of the roller 6 fits into the shaft hole 5d of the rocker arm 5 at both ends 7b, 7b '. Hardened to a hardness higher than That is, the roller shaft 7 has a central portion 7a having a high hardness to enhance the wear resistance with respect to the roller 6, and both ends 7b and 7b 'have a low hardness to improve the crimping property. The hardening of the roller shaft 7 is performed by, for example, induction hardening.

The roller shaft 7 penetrates the shaft hole 6a of the roller 6, the central portion 7a pivotally supports the roller 6, and both ends 7b and 7b 'are fitted into the shaft hole 5d. Caulking 7d and 7d 'are applied respectively, and the diameter of the vicinity of the opening end is expanded over the entire peripheral edge. Especially, the portion of the shaft hole 5d facing each chamfer 5e, 5e' is greatly expanded and the shaft hole 5d is caulked. It is fixed. Then, after the roller shaft 7 is caulked and fixed to the rocker arm 5, pin holes 5g and 7e are bored from the end surface 5f of the rocker arm 5 perpendicularly to the shaft hole 5d and the one end 7b 'of the roller shaft 7. As described above, the one end 7b 'of the roller shaft 7 has a low hardness, and therefore the pin hole 7e can be easily formed.

The pin 8 is set to be longer than the sum of the length of the pin hole 5 g of the rocker arm 5 and the pin hole 7 e of the roller shaft 7 (thickness of the roller shaft 7). It is driven through the holes 5g and 7e, and its tip 8a projects inward from the pin hole 7e to approximately the center. The pin 8 is, for example, a spring pin, and is expanded in the pin holes 5g and 7e by a spring property and pressed against the inner surface so that the pin 8 cannot be deviated.

In this way, the roller shaft 7 is firmly fixed to the rocker arm 5 by the caulks 7d and 7d 'and the pin 8 so as not to deviate in the axial direction and not to rotate. The head 8b of the pin 8 is slightly recessed in the pin hole 5g so that it does not interfere with the cam. Further, the pin 8 is not limited to the spring pin, and a normal straight pin may be used and press-fitted into the pin holes 5g and 7e.

The rocker arm 5 is pivotally supported by a rocker shaft that penetrates a central shaft hole 5a so that a roller 6 at one end 5b serves as a cam of a cam shaft and the other end (not shown) serves as the valve adjusting screw. It is brought into contact with the valve stem head via the valve stem head and swings with the rotation of the cam shaft to open and close the valve. The operation will be described below.

The rocker arm 5 swings with the rotation of the cam shaft to open and close the valve, and the roller 6 rolls while being pressed against the cam surface and rotates with respect to the roller shaft 7. Along with this, the roller shaft 7 receives the rotational torque from the roller 6. However, since both ends of the roller shaft 7 are fixed to the rocker arm 5 by the caulking 7d and 7d 'and are further prevented from rotating by the pin 8, the roller shaft 7 is firmly fixed to the rocker arm 5. Therefore, the roller shaft 7 does not rotate even if it receives a torque from the roller 6, and the caulks 7d and 7d 'do not loosen.

Further, the roller shaft 7 has excellent wear resistance because the central portion 7a that supports the roller 6 is hardened with high hardness, and therefore wear due to rotation of the roller 6 is significantly reduced. , Durability is improved.

[0017]

[Effect of the device]

 As described above, according to the present invention, since the roller shaft is firmly fixed to the rocker arm by the caulking and the pin, the roller shaft does not rotate even if it receives the rotational torque as the roller rotates, and the caulking is prevented. It does not sag. In addition, the roller shaft is excellent in wear resistance because the part supporting the roller is hardened with high hardness, and the durability is improved. In addition, there is an effect that it is easy to form a pin hole for press-fitting the pin.

[Brief description of drawings]

FIG. 1 is a partial side view of a conventional roller rocker arm.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a partial side view showing an embodiment of a rocker arm according to the present invention.

FIG. 4 is a sectional view taken along the line IV-IV in FIG.

[Explanation of symbols]

 5 Rocker arm 6 Roller 7 Roller shaft 8 pin

Claims (1)

[Scope of utility model registration request] 1. A rocker arm in which a roller is used in a contact portion with a cam, and both ends of a roller shaft pivotally supported in a shaft hole of the rocker arm are fixed by caulking.
A roller shaft having a central portion axially supporting the roller and having a hardness higher than both ends axially supported by a shaft hole of a rocker arm,
A rocker arm comprising a pin hole press-fitted into each of the pin holes formed in the shaft hole of the rocker arm and one end of the roller shaft to fix them.