JPH0487747A - Temporary deformation method for cylinder head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for forming cam holes, etc. in a cylinder head.
The present invention relates to a method of temporarily deforming a cylinder head by pressing the cylinder head into a bowed state, which is the same as the state in which the cylinder head is assembled to a cylinder block.

[Conventional technology]

In the conventional method for temporarily deforming a cylinder head, as shown in FIG. 4, first, an elongated plate-shaped shim 2 is placed on a flat jig plate 1, and a cylinder head 3 is placed on top of the shim 2. At this time, the shim 2 is arranged so as to cross the cylinder head 3 at a right angle in the middle of the camshaft.

Next, in all hend bolt holes 4 of the cylinder head 3,
Insert the hydraulic cylinder 5 from above and bring it into contact with the seat surface 4a of the head bolt hole 4, and when assembling it to the cylinder block, orient the seat surface 4a toward the jig plate 1 using the same axial force as when assembling it to the cylinder block. Press it.

The cylinder head 3 is brought into the same arched state as when it is assembled to the cylinder block by the pressing described above, and cam holes 6 and the like are formed in the cylinder head 3.

[Problems to be Solved by the Invention] However, in the conventional cylinder head temporary deformation method, a large number of hydraulic cylinders 5 are required, such as 10 hydraulic cylinders 5 for 4 cylinders and 14 hydraulic cylinders 5 for 6 cylinders. The problem is that the equipment becomes complicated.

Furthermore, if the head bolt hole 4 is located on the cam journal, there is a problem in that the position of the head bolt hole 4 is restricted, such as making it impossible to machine the cam hole 6 in that area.

The present invention has been made in view of these conventional problems, and aims to provide a method for temporarily deforming a throat into a cylinder that requires fewer hydraulic cylinders and does not affect the position or number of head bolt holes. ing.

[Means for Solving the Problems] In order to solve the above object, the cylinder head temporary deformation method of the present invention is such that the cylinder head cam is placed on a flat jig plate on which an elongated plate-shaped gym is mounted. By mounting the cylinder head so that the shim crosses the middle part in the shaft axial direction at right angles, and further abutting a clamp plate on the upper surface of the cylinder head and pressing the clamp plate toward the jig plate. , the cylinder head is in an arched state.

[Operation] By pressing the clamp plate that is in contact with the upper surface of the cylinder head toward the jig plate from above using a hydraulic cylinder or the like, the cylinder head is pressed toward the jig plate. At this time, since a shim is in contact with the lower part of the throat of the cylinder, the cylinder head arches around the shim, which is the same state as when it is assembled to the cylinder block. If the cam holes etc. are machined in this state, when the cylinder head is actually assembled to the cylinder block, the coaxiality, etc. of the machined cam holes will be in the optimum position and shape.

Since the pressing is performed through the crank plate, the cylinder head can be assembled to the cylinder block without being affected by the number or position of the head bolt holes.

The bowed state of the cylinder head can be adjusted by adjusting the position and thickness of the shim to approximate the state assembled in the cylinder block.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

In this example, the cylinder to be temporarily deformed - The throat 3 is connected to a four-cylinder cylinder as shown in Fig. 1 - The throat 3 connects the four spark plug holes 7 in the upper center along the axial direction of the camshaft. A cam hole machined part 8 is provided along the axial direction of the camshaft on both sides of the row of spark plug holes, and a head bolt hole 4 is formed in the cam hole machined part. The cam hole processing portion 8 is supported from below by a rib (not shown).

The structure of the jig used to temporarily deform the cylinder head 3 includes a jig plate 1 made of a plate with a flat top surface, and a shim 2 made of a long and thin plate with a thickness of about 30 μm.
In addition, three clamp plates 9 are placed on the cylinder head 3, and the clamp plates 9 are pressed from above by the hydraulic cylinder 5. The three clamp plates 9 include two clamp plates 9a each made of an elongated rectangular parallelepiped with two notches 9C at the bottom, and two clamp plates having the shape described above at a predetermined interval in the width direction. It consists of a single clamp plate 9b arranged in parallel and connected via another member to form an H-shape on the upper surface. Note that the position of the cutout portion 9C is as follows:
When the cylinder head 3 comes into contact with the upper surface of the cylinder head 3, the cam hole 6 is provided at a position facing above the part to be machined.

As shown in FIG. 2, the method for temporarily deforming the cylinder head using the jig having the above-mentioned configuration is to first place the cylinder head 3 on the jig plate l on which the shim 2 is placed. At this time,
The shim 2 is arranged to cross the camshaft axis direction of the cylinder head 3 at right angles between the second cam hole machined part 8 and the third cam hole machined part 8 from the left.

Next, three clamp plates 9 are placed on the upper surface of the cylinder head 3. The clamp plate 9 is placed on a clamp plate made of an elongated rectangular parallelepiped so that the longitudinal direction of the clamp plate 9a is opposed to a pair of cam hole machined portions 8 arranged in the width direction at both ends of the cylinder head 3 in the camshaft axial direction. Place two sheets of 9a. Further, parallel rectangular parallelepiped portions of the upper surface H-shaped glue lamp 9b are placed across the pair of cam hole machined portions 8a in the width direction located at the center of the upper surface of the cylinder head 3. In the above-mentioned arrangement, the longitudinal direction of the two rectangular parallelepiped portions faces in the width direction of the cylinder head, and the rectangular parallelepiped portions are placed in the cam hole processing portion 8.

Next, the three clamp plates 9 are pressed from above by the hydraulic cylinder 5, and the cylinder head 3 is temporarily deformed into a bow shape with both axial ends lowered to the same state as when assembled to the cylinder block. After the cylinder head 3 is arched, a cam hole 6 is machined in the cylinder head 3, and when the predetermined processing is completed, the clamp plate 9 is removed.

In the method for temporarily deforming the cylinder head described above, the thickness of the shim is set to about 30 μm, and the shim is inserted between the second and third cam hole processing parts 8 from the left to adjust the arched state of the cylinder head 3. However, this was determined as follows.

The cam hole 6 is machined without temporarily deforming the cylinder head 3, the cylinder head 3 is assembled to the cylinder block, and the amount of deformation of the coaxiality of the machined cam hole 4 is determined by the graph shown in Fig. 3. Became. according to this,
It was found that the amount of deformation of the cam hole 6 of the third cam hole machined part 8 was the largest, and the amount of deformation of the cam hole 6 of the second cam hole machined part 8 was the second largest. I decided to place shim 2 between the second and third positions (and closer to the third position). In addition, the maximum deformation amount is 36 μ first order is 19
Since the thickness of the shim was 30μ, the thickness of the shim was set to about 30μ.

As described above, in the cylinder head temporary deformation method of this embodiment, the cylinder head 3 is deformed by abutting the clamp plate 9 on the upper surface of the cylinder head 3 and pressing the clamp plate 9 from above. Furthermore, the cylinder head 3 can be deformed into a bowed state without being affected by the position of the head bolt holes 4 or the number thereof.

Further, by simply pressing the top surface of the cylinder head 3 at three points, the cylinder head 3 can be easily transformed into a state where it is assembled to a cylinder block compared to the conventional method.

In this embodiment, the clamp plate 9 is brought into contact with the cam hole processing portion 8 which has a rib extending to the lower part so that no deformation remains in the cylinder head 3 after the pressing by the clamp plate 9 is stopped.

〔Effect of the invention〕

As explained above, in the method for temporarily deforming a cylinder head of the present invention, in order to deform the cylinder head by pressing the upper surface of the cylinder head with a clamp plate, the cylinder head can be bent into an arched shape without being affected by the number or position of head bolts. This has the effect of being able to temporarily transform the state.

Another advantage is that the cylinder head can be temporarily deformed into a state assembled to the cylinder block more easily than in the past by simply pressing the cylinder head through the clamp plate.

[Brief explanation of the drawing]

Figure 1 is a perspective view with the clamp plate removed from the cylinder head, Figure 2 (a) is a top view of the same with the clamp plate in contact, Figure 2 (b) is a side view of the same, and Figure 3 is the cam. FIG. 4(a) is a perspective view showing an example of a conventional method for temporarily deforming a cylinder head, and FIG. 4(b) is a sectional view taken along the line I--I.

Claims (1)

[Claims] (1) Place the cylinder head on a flat jig plate on which an elongated plate-shaped shim is placed so that the shim crosses the middle part of the cylinder head in the axial direction of the camshaft at right angles,
Further, a temporary deformation of the cylinder head is characterized in that the cylinder head is brought into a bowed state by abutting a clamp plate against the upper surface of the cylinder head and pressing the clamp plate toward the jig plate. Method.