JPH0511281Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to an engine valve drive device.

(Prior art) Conventionally, in engine valve drive devices, one end of the rocker arm has been formed into a fork shape in order to reduce the sliding resistance between the rocker arm and the valve drive cam and improve the valve drive characteristics. It is known that a roller is rotatably attached to this part via a roller shaft, and the rocker arm and valve drive cam are brought into rolling contact via this roller (for example, −
See Publication No. 88016. ) By the way, when the roller is rotatably supported in the fork part of the rocker arm via the roller shaft, the roller shaft is usually inserted into the shaft hole formed in the fork part of the rocker arm, and then the roller shaft is Both ends are caulked to prevent the roller shaft from coming off.

However, this method of preventing the roller shaft from coming off by caulking requires skill in the caulking process itself, and when preventing the shaft from coming off by caulking, press-fitting of the roller shaft is usually used in conjunction with this method. Since press-fitting requires a high degree of fitting precision, there are problems in that the work tends to be uncertain and the workability is poor.

Furthermore, although the relative displacement in the axial direction between the roller shaft and the fork portion of the rocker arm can be restricted by caulking the roller shaft, the relative displacement in the axial direction between the roller and the fork portion cannot be restricted. There was also a risk that the rocker arm would be slid and displaced in the axial direction, and the side surface and the fork portion would come into rotational contact with each other, causing contact wear on the fork portion, thereby impairing the durability of the rocker arm.

(Purpose of the invention) The present invention is an attempt to solve the problems pointed out in the above-mentioned section of the prior art. The purpose of this invention is to more reliably and easily fix a roller shaft to a fork portion of a rocker arm in a valve drive device, and to improve the durability of the rocker arm.

(Means for Achieving the Object) The present invention, as a means for achieving the above object, uses a valve drive cam that is swingably supported by a rocker shaft and transmits the displacement of the valve drive cam to the intake and exhaust valves as a valve operating force. A fork portion is formed at one end of the Rocker arm on the valve driving cam side, and a roller is rotatably attached to the fork portion via a roller shaft, and the roller is brought into contact with the valve driving cam. In the device, the fork portion of the rocker arm includes a cylindrical portion interposed between a shaft hole formed in the fork portion and a roller shaft fitted into the shaft hole, and a fork portion located on one end side of the cylindrical portion. and a flange interposed between a side surface of the roller shaft and a side surface of the roller, and a collar section located at the other end of the cylinder section and bent at least radially inward to engage with the end of the roller shaft in its axial direction. The insert is provided with a locking pawl portion that restricts the axial displacement of the roller shaft.

(Function) In the present invention, by the above means, (1) the flange of the insert positions the roller in the axial direction with respect to the fork part of the rocker arm, and prevents mutual contact between the fork part and the side surface of the roller; (2) By bending the retaining claw portion of the insert inward in the radial direction when the roller shaft is inserted, the retaining claw portion ensures that the roller shaft comes out of the fork portion in the axial direction. The following effects can be obtained:

(Embodiment) Hereinafter, a preferred embodiment of the present invention will be described with reference to FIGS. 1 to 3.

FIG. 1 shows the main parts of the valve train of an automobile engine equipped with a valve drive device according to an embodiment of the present invention, and in the figure, reference numeral 1 indicates the main body of the present invention, which will be described in detail later. The rocker arm 2 is a rocker shaft that swingably supports the center portion of the rocker arm 1.

The rocker arm 1 has, at one end 1a, a bifurcated fork portion 11 consisting of a pair of left and right projecting pieces 12 and 13, as shown in FIG. A roller 3 that rolls into contact with the cam surface of the valve drive cam 21 is rotatably attached to the fork portion 11 by a roller shaft 4. In this case, in this embodiment, by applying the present invention, two inserts 5, which will be described later, are provided in the fork portion 11 of the rocker arm 1, and these two inserts 5, 5 allow the fork portion 11 and the roller 3 to be aligned in the axial direction. The positioning of the roller shaft 4 and the prevention of the roller shaft 4 from coming off the fork portion 11 are simultaneously performed.

The insert 5 is inserted into the cylindrical portion 15 as shown in FIG.
A flange portion 16 is formed at one end, and two first latching claw portions 17, 17 and two second latching claw portions 18, 18 are formed at the other end, respectively. There is. The cylindrical portion 15 of the insert 5 has an outer diameter that allows it to fit into the shaft hole 25 provided in the fork portion 11 and an inner diameter that allows it to be press-fitted into the roller shaft.
It has an axial length approximately corresponding to the thickness dimension of each protruding piece 12, 13. In addition, the flange 16 of the insert 5
The thickness dimension is set to be slightly smaller than the dimension corresponding to 1/2 of the difference between the distance between the pair of left and right projections 12 and 13 of the fork portion 11 and the axial width dimension of the roller 3. .

Furthermore, the first latching claw portion 1 of the insert 5
7, 17 and the second latching claw portions 18, 18 are composed of four circular arc-shaped protrusions arranged alternately in the circumferential direction, and this corresponds to an extension of the cylindrical portion 15. It is formed by inserting four slits 19, 19... into the cylinder. In the first state, the first latching claw part 17 and the second latching claw part 18 are connected to the cylindrical part 1, respectively, as shown in FIG.
5, but in the second state, the first latch claw portion 17 is bent radially inward from the boundary line l with the cylindrical portion 15 as shown by arrow a. Then, the second hook portion 18 is bent radially outward from the boundary line 1 as a base point, as shown by arrow b (see FIGS. 1 and 2). In its second state, the first locking pawl 17 engages with the end surface 4a of the roller shaft 4 and acts to restrict the axial displacement of the roller shaft 4 (that is, in this embodiment teeth,
This first latching claw part 17 corresponds to the latching claw part in the scope of the utility model registration claim). On the other hand, the second locking claw part 18 is capable of holding the protrusion 12 or 13 of the fork part 11 together with the collar part 16 in its second state.

In addition, in Fig. 1, the reference numeral 22 indicates the engine intake
It's an exhaust valve.

Next, the fork part 1 of this Rocker arm 1
The work of assembling the roller 3 into the roller 1 will be briefly described in the order of work.

First, each of the protrusions 12 and 13 of the fork portion 11 of the Rocker arm 1 in a single state is injected with a first
A pair of inserts 5, 5 whose shape is maintained in the state of
each protrusion 1 from the inside of the fork part 11.
2, 13 into the shaft holes 25, 25, and with the flange 16 in contact with the inner surfaces 12a, 13a of each protruding piece 12, 13, bend the second latch claw parts 18, 18. Each of the inserts 5, 5 is attached to a protruding piece 1.
2 and the projecting piece 13 side.

Next, a pair of left and right inserts 5 are attached to the protrusions 12 and 13 of the fork portion 11, respectively.
The roller 3 is inserted between each of the collar portions 16, 16 of the roller 3, and the roller 3 and each insert 5, 5 are arranged coaxially.

In this state, insert the roller shaft 4 into the insert 5.
and is inserted into the roller 3 from one side thereof, and the roller 3 is supported on the fork portion 11 by the roller shaft 4. At this time, roller 3 and roller shaft 4
Although the roller shaft 4 and the insert 5 are loosely fitted, it is preferable that the roller shaft 4 and the insert 5 are press-fitted.

Next, each of the first hook portions 17, 17, . . . of the inserts 5, 5 is bent inward.

This completes the attachment of the roller 3 to the fork portion 11 of the rocker arm 1.

As described above, according to the structure of the present invention, when the roller shaft 4 is inserted into the inserts 5, 5 and the roller 3, each of the first latching claws 17, 17... of the inserts 5, 5 is Since the mechanism for preventing the roller shaft 4 from coming off from the fork portion 11 is constructed only by bending it inward in the radial direction, the above-mentioned conventional example in which the roller shaft is prevented from coming off by caulking the end of the roller shaft is constructed. Therefore, the operator's skill level is not required so much, and the work can be done easily and reliably, and work efficiency is greatly improved.

Further, the collar portion 16 of the insert 5 positions the fork portion 11 and the roller 3 in the axial direction, and at the same time prevents the protrusions 12 and 13 of the fork portion 11 from coming into contact with the roller 3. Therefore, the protrusions 12 and 13 will not wear out due to contact with the roller 3, and the durability of the rocker arm 1 will be improved accordingly.

Furthermore, according to this structure, when fixing the roller shaft 4 to the fork portion 11, there is no need to hit the roller shaft 4, for example, the roller shaft 4 is made of a ceramic material with poor impact resistance. In such a case, the roller shaft 4 will not be damaged and can be said to be a particularly suitable structure.

Further, in the above embodiment, the insert 5 is provided with the second latching claw portions 18, 18, but in other embodiments of the present invention, this may be omitted.
Alternatively, it can be bent radially inward in the same way as the first latch claw part 17 to function as a member for preventing the roller shaft 4 from coming off.

(Effects of the invention) The present invention forms a fork portion at one end on the valve-driving cam side of the Rocker arm that is swingably supported by the Rocker shaft and transmits the displacement of the valve-driving cam to the intake and exhaust valves as a valve-driving operating force. In addition, in the engine valve driving device, a roller is rotatably attached to the fork portion via a roller shaft, and the roller is brought into contact with the valve operating cam, and the fork portion is formed on the fork portion of the rocker arm. a cylindrical portion interposed between the shaft hole and the roller shaft fitted therein; and a cylindrical portion located at one end of the cylindrical portion and interposed between a side surface of the fork portion and a side surface of the roller. a collar portion, and a locking pawl located at the other end of the cylindrical portion and bent at least radially inward to engage with the end portion of the roller shaft in its axial direction to restrict axial displacement of the roller shaft. The invention is characterized in that it includes an insert having a section.

Therefore, according to the engine valve drive device of the present invention, (1) the flange of the insert positions the roller in the axial direction with respect to the fork part of the rocker arm, and the fork part and the side surface of the roller are in mutual contact with each other; (2) The latch claw of the insert is moved radially inward when the insert is inserted into the roller shaft. By bending, the latching pawl reliably restricts the roller shaft from coming out of the fork in the axial direction, so for example, as in the conventional example, caulking the roller shaft prevents the roller shaft from coming off. Practical effects such as the ability to securely and easily fix the roller shaft to the fork portion can be obtained compared to a structure in which the roller shaft is fixed.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a main part of a valve train of an engine equipped with a valve drive device according to an embodiment of the present invention, and FIG.
The figure is a vertical sectional view of the main part of Figure 1, and Figure 3 is a longitudinal cross-sectional view of the main part of Figure 1.
FIG. 3 is an enlarged perspective view of the insert shown in the figure. 1...Rotzker arm, 2...Rotzker shaft, 3...Roller, 4...Roller shaft, 5...
...Insert, 11...Fork part, 12, 13
... Projection piece, 15 ... Cylinder part, 16 ... Flange part, 17,
18...Latching claw portion, 19...Slit, 21...
Valve drive cam, 22... intake/exhaust valve.

Claims (1)

[Scope of utility model registration request] A fork portion is formed at one end on the valve cam side of the rocker arm that is swingably supported by the rocker shaft and transmits the displacement of the valve cam to the intake and exhaust valves as a valve operating force, and a roller shaft is attached to the fork portion. A valve drive device for an engine, in which a roller is rotatably mounted through the valve drive cam, and the roller is brought into contact with the valve drive cam, and the fork portion of the rocker arm is provided with a shaft hole formed in the fork portion and fitted into the shaft hole. a cylindrical portion interposed between the roller shaft to be inserted; a flange portion located on one end side of the cylindrical portion and interposed between the side surface of the fork portion and the side surface of the roller; and the cylindrical portion. an insert having a locking claw located at the other end and bent at least radially inward to engage with the end of the roller shaft in the axial direction to restrict axial displacement of the roller shaft; A valve drive device for an engine, characterized in that it is provided with: