JP4257167B2 - Cylinder head manufacturing method and apparatus - Google Patents

Description

  The present invention relates to a cylinder head casting method and apparatus for casting a camshaft journal hole of a cylinder head with a casting pin.

  In general, a camshaft journal hole for supporting a camshaft is provided in a cylinder head constituting an internal combustion engine. For this reason, as described in Patent Document 1, when casting a cylinder head, a pin-shaped core corresponding to the camshaft journal hole, a so-called cast pin is used.

  More specifically, the cylinder head casting apparatus includes a lower die having a substantially rectangular plane, and a set of first sliding dies disposed at one end and the other end of the lower die so as to face each other. A pair of second sliding molds arranged to face each other in a direction orthogonal to the axial direction of the first sliding mold, and an upper mold approaching or separating from the lower mold, The cast pin is disposed in each of the first sliding molds. Further, the upper die is provided with a hole through which the core pin is inserted.

  The casting of the cylinder head by this casting apparatus is performed as follows. That is, first, each first sliding mold is displaced toward the lower mold, and then each second sliding mold is displaced toward the lower mold. Each first sliding mold is provided with a protruding locking member, while each second sliding mold has a locking member provided with a recess. When the second sliding mold is displaced and the mold is clamped after the displacement of the first sliding mold is completed, the first sliding type locking members are engaged with the second sliding type locking members. Thus, the first sliding mold is positioned and fixed.

  Next, the cast pin is moved forward, the cast pin is inserted into the hole of the upper mold, and then poured into the cavity. As the molten metal cools and solidifies, a cylinder head that is a cast product is obtained.

  Thereafter, the cylinder pin can be taken out by retreating the cast pin, retreating the second sliding mold and the first sliding mold in this order, and further separating the upper mold from the lower mold. .

JP 2003-88940 A

  However, in the above-described prior art, after the first sliding die is positioned and fixed by the second sliding die, it is necessary to temporarily retract the casting pin in order to avoid the upper die from interfering with the casting pin. is there. For this reason, the time from when the first sliding mold is operated until the mold opening is completed becomes relatively long.

  Further, in order to reliably insert the core pin into the hole portion of the upper mold, the hole diameter of the hole portion is set to be relatively larger than the diameter of the core pin. That is, when the core pin is inserted through the hole, a relatively large clearance is formed between the inner wall surface of the hole and the outer wall surface of the core pin. For this reason, in order to obtain the dimensional accuracy of the camshaft journal hole, a precise finishing process is required.

  The present invention solves this type of problem, and can easily and reliably cast the camshaft journal hole of the cylinder head with a simple and inexpensive configuration, thereby shortening the manufacturing cycle and the cylinder. It is an object of the present invention to provide a cylinder head manufacturing method and a manufacturing apparatus thereof that can obtain the head at low cost.

In order to achieve the above object, the present invention provides a method of manufacturing a cylinder head having a camshaft journal hole by casting,
A step of clamping the mold by displacing a set of first sliding molds arranged at positions opposed to each other toward a positioning-fixed lower mold;
A step of clamping the mold by displacing an upper mold having a hole along the axial direction of the camshaft journal hole toward the lower mold; and
Position the swingable core pin by being passed through the bearing support, respectively, and facing each other along the axial direction of the camshaft journal hole in a state linked Rutotomoni clearance is formed the elastic member A pair of second sliding dies disposed on the lower die is displaced toward the lower die and clamped to form a cavity, and the cast pin and the upper die are swung to swing. Inserting the core pin into the hole while centering with the hole ;
Pouring molten metal into the cavity;
Cooling and solidifying the molten metal to obtain a cylinder head in which a camshaft journal hole is formed at a position corresponding to the core pin, and then retreating each core pin; and
A step of opening each mold by retreating the second sliding mold together with the core pin;
Opening each of the first sliding molds by retreating the mold;
A step of opening the mold by separating the upper mold from the lower mold;
It is characterized by having.

Further, the present invention is a manufacturing apparatus for a cylinder head having a core pin for casting the camshaft journal hole of the cylinder head,
A lower mold with fixed positioning;
A set of first sliding molds facing each other and approaching or separating from the lower mold;
A set of second sliding molds that face each other at a position different from the first sliding mold and that move forward and backward along the axial direction of the camshaft journal hole;
A pair of cast pins that are supported in a swingable manner by passing through a bearing provided in each of the second sliding molds in a state where a clearance is formed ;
A resilient member that constantly urges and biases the cast pin supported by one of the second sliding molds toward the remaining second sliding mold that faces the other;
A drive mechanism capable of advancing and retracting each core pin in the axial direction and capable of advancing and retracting each second sliding mold in the axial direction;
An upper mold that forms a cavity with the lower mold, the set of the first sliding mold, and the set of the second sliding mold;
Equipped with a,
When the mold pin is inserted into the hole formed in the upper mold at the time of clamping, the core pin is pivoted to center the mold pin and the hole .

  According to the present invention, after the upper mold is closed, the core pin is passed through the hole of the upper mold. For this reason, it is not necessary to move the core pin backward. Therefore, since the time from when the first sliding mold is operated to when the mold opening is completed can be relatively shortened, the manufacturing efficiency of the cylinder head is improved.

  In addition, according to the present invention, the core pin is connected to be swingable by the elastic member. For this reason, even if the position of the core pin and the hole portion of the upper mold is slightly shifted, the core pin is swung so that it can be reliably inserted into the hole portion. For this reason, center alignment of the core pin and the hole, that is, so-called centering is facilitated. Therefore, the dimensional accuracy of the camshaft journal hole can be ensured.

  In addition, according to the present invention, the core pin is moved backward before the second sliding die, so that the core pin is released from the restraining force of the solidified cylinder head. For this reason, since the second sliding mold can be easily moved backward, a small drive mechanism is sufficient for the casting pin and the second sliding mold to move backward. Therefore, there is an advantage that the structure of the casting apparatus is simplified and the capital investment for the casting apparatus can be reduced.

  According to the present invention, the time until the mold opening is completed can be relatively shortened, and as a result, the manufacturing efficiency of the cylinder head is improved.

  In addition, since the core pin is pivotably connected via the resilient member, the core pin can be securely inserted into the hole, and the center of the core pin and the hole can be adjusted. It becomes easy. For this reason, the dimensional accuracy of the camshaft journal hole is improved.

  In addition, since the second sliding mold is moved backward after the cast pin is released from the restraining force of the solidified cylinder head, the cast pin and the second slide are driven even if the drive mechanism is small. The mold can be moved backward easily. Therefore, the configuration of the casting apparatus is simplified, and the capital investment for the casting apparatus can be reduced.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a cylinder head manufacturing method according to the present invention in relation to a cylinder head casting apparatus for carrying out the method will be described below in detail with reference to the accompanying drawings.

  First, FIG. 1 shows a schematic partial cross-sectional view of a main part of a cylinder head which is a cast product. The cylinder head 1 is provided with outer wall portions 2a and 2b and partition wall portions 3a to 3c. The outer wall portion 2a and the partition wall portions 3a and 3b are formed with tapered holes 4a to 4c having a diameter reduced toward the partition wall portions 3a and 3b from the outer wall portion 2a, while the outer wall portion 2b and the partition wall are formed. The portion 3c is formed with tapered holes 5a and 5b that are reduced in diameter toward the partition wall portion 26c from the outer wall portion 2b. The taper holes 4a to 4c and the taper holes 5a and 5b constitute a camshaft journal hole 6 for inserting a camshaft (not shown).

  The diameter-reduced side end diameter of the tapered hole 4a and the diameter-expanded side end diameter of the tapered hole 4b are set to the same dimension. Similarly, the diameter of the reduced diameter side end of the tapered hole 4b and the diameter of the enlarged diameter side end of the tapered hole 4c are set to the same dimension. It is set to the same dimension as the diameter on the enlarged diameter side.

  FIG. 2 is a schematic overall perspective view of a casting apparatus for a cylinder head (hereinafter also simply referred to as a casting apparatus) for casting such a cylinder head 1, FIG. 3 is a plan view of the relevant part, and FIG. Are shown in FIG. The casting apparatus 10 includes a lower mold 12 that is positioned and fixed, a set of first sliding molds 14a and 14b that can be moved forward and backward in the direction of arrow A, and a set that can be advanced and retracted in the direction of arrow B perpendicular to the direction of arrow A. The second sliding molds 16a and 16b and the upper mold 18 that can be moved up and down at a position facing the lower mold 12 are clamped, whereby the cavity 20 (corresponding to the shape of the cylinder head 1). 3 and 4) are formed.

  The first sliding mold 14a corresponds to the intake side of the cylinder head 1 (see FIG. 1) to be cast, and the first sliding mold 14b corresponds to the exhaust side of the cylinder head 1. The second sliding type 16a corresponds to the transmission case side of the cylinder head 1, and the second sliding type 16b corresponds to the timing chain (or timing belt) side.

  The lower mold 12 is provided with four gates 22, and each gate 22 communicates with a sealed container for storing molten metal (not shown).

  Further, as shown in FIG. 2, first guide rails 24 a and 24 b extending along the arrow A direction are provided on the lower mold 12, and a second guide rail extending along the arrow B direction is provided. 26a and 26b are provided. Among these, the first sliding molds 14a and 14b are disposed on the first guide rails 24a and 24b, while the second sliding molds 16a and 16b are disposed on the second guide rails 26a and 26b. .

  The first sliding dies 14a and 14b are displaced while being guided by the first guide rails 24a and 24b by cylinders 28a and 28b as driving mechanisms, respectively. That is, rods 30a and 30b that constitute cylinders 28a and 28b and move forward and backward along the direction of arrow A are connected to the first sliding dies 14a and 14b.

  In addition, the recessed parts 32a-32d are provided in the end surface of the 1st sliding type | molds 14a and 14b. When the mold clamping is performed, the second sliding molds 16a and 16b enter the recesses 32a to 32d (see FIG. 3).

  Each of the second sliding molds 16a and 16b constitutes a cylinder 34a and 34b as a driving mechanism, and the rods 36a and 36b move forward and backward along the arrow B direction. The lower mold 12 is approached or separated while being guided. The rods 36a and 36b are connected to the second sliding molds 16a and 16b via fixing members 38a and 38b and pressing block bodies 40a and 40b.

  The second sliding dies 16a and 16b support cast pins 42a and 42b that are slidable in the direction of arrow B, respectively. Specifically, as shown in FIGS. 4 and 5, the second sliding dies 16a and 16b are provided with through holes 44a and 44b, respectively, and the core pins 42a and 42b are connected to the through holes 44a, 44b. Here, the clearance between the bushes 46a, 46b disposed in the through holes 44a, 44b and the core pins 42a, 42b is approximately as compared with that between the core pins 42a, 42b and the upper die 18. It is set to a relatively large value of about 100 times.

  As can be seen from FIG. 6, cooling channels 50a and 50b are formed inside the core pins 42a and 42b via pipes 48a and 48b. The cooling channels 50a and 50b The pipes 52a and 52b communicate with the outlet pipes 54a and 54b. The outer shape of the core pins 42a and 42b corresponds to the camshaft journal hole 6, and the core pin 42a has a tapered shape corresponding to the taper holes 4a to 4c. 42b has a tapered shape corresponding to the tapered holes 5a and 5b. Further, large diameter portions 56a and 56b are provided at one end portions of the core pins 42a and 42b.

  As shown in FIG. 5, the pressing block bodies 40a and 40b include support plates 58a and 58b provided with cylindrical concave portions 57a and 57b having shapes corresponding to the large diameter portions 56a and 56b, and the cylindrical concave portions 57a, The retaining plates 60a and 60b cover a part of the opening 57b. Of these, the support plates 58a and 58b are provided with spring accommodating chambers 62a and 62b communicating with the cylindrical recesses 57a and 57b, respectively, and disc springs 64a and 64b are accommodated in the spring accommodating chambers 62a and 62b. ing.

  The dimensions of the cylindrical recesses 57a and 57b along the arrow B direction are slightly longer than the large diameter portions 56a and 56b of the core pins 42a and 42b. For this reason, the bottom end surfaces of the large-diameter portions 56a and 56b accommodated in the columnar recesses 57a and 57b have a predetermined clearance from the bottom surfaces of the columnar recesses 57a and 57b when they are elastically biased by the disc springs 64a and 64b. Separate with.

  As described above, part of the openings of the columnar recesses 57a and 57b are covered with the retaining plates 60a and 60b. For this purpose, the diameter of the columnar recesses 57a and 57b is reduced, whereby the large-diameter portion 56a. , 56b are prevented from coming off from the support plates 58a, 58b.

  As shown in FIG. 3, guide rods 66a and 66b are screwed onto both sides of the core pins 42a and 42b in the pressing block bodies 40a and 40b. That is, a pair of stepped holes 68a and 68b are provided on both sides of the through holes 44a and 44b into which the core pins 42a and 42b are slidably inserted. The heads 70a and 70b of the guide rods 66a and 66b are inserted into the stepped holes 68a and 68b. The heads 70a and 70b are freely engageable with the ends of the stepped holes 68a and 68b. It is.

  As shown in FIG. 4, the upper mold 18 protrudes toward the cavity 20 and protrudes 72 a to 72 d for forming a space between the outer wall portions 2 a and 2 b of the cylinder head 1 and the partition wall portions 3 a to 3 c. The protrusions 72a, 72b and 72d are respectively provided with through holes 74 penetrating in the axial direction (arrow B direction) of the camshaft journal hole 6.

  Next, the operation of the casting apparatus 10 configured as described above will be described based on the flowchart shown in FIG.

  The first sliding die 14a corresponds to the intake side of the cylinder head 1, and the first sliding die 14b corresponds to the exhaust side. The second sliding mold 16a corresponds to the mission case side, and the second sliding mold 16b corresponds to the timing chain (or timing belt) side.

  First, in step S1, the cylinders 28a and 28b are energized to cause the rods 30a and 30b to move forward toward the lower mold 12. As a result, the first sliding molds 14a and 14b are displaced while being guided by the first guide rails 24a and 24b, and finally come into contact with the lower mold 12.

  Next, in step S2, the upper mold 18 is lowered. That is, the upper mold 18 is clamped with respect to the lower mold 12 and the first sliding molds 14a and 14b.

  Next, in step S3, the cylinders 34a and 34b are energized. As a result, the rods 36a and 36b move forward, and as a result, the lower mold 12 and the first sliding molds 14a and 14b are clamped while the second sliding molds 16a and 16b are guided by the second guide rails 26a and 26b. And it is displaced toward the upper mold 18. Finally, the second sliding molds 16a and 16b come into contact with the lower mold 12, the first sliding molds 14a and 14b, and the upper mold 18 to complete the mold clamping. Note that the second sliding molds 16a and 16b enter the recesses 32a to 32d provided on the end surfaces of the first sliding molds 14a and 14b during mold clamping.

  At this time, the casting pin 42a is pressed forward by the fixing member 38a and the pressing block body 40a, and the head protruding from the second sliding die 16a is a through hole of the protrusions 72a and 72b of the upper die 18. 74, 74, and faces the protrusion 72c leaving a very small clearance. On the other hand, in the remaining cast pin 42b that has been moved forward by being pressed by the fixing member 38b and the pressing block body 40b, the head protruding from the second sliding die 16b is the through hole 74 of the protruding portion 72d of the upper die 18. And is opposed to the other end surface of the protrusion 72c leaving a slight clearance.

  As described above, in the present embodiment, the core pins 42a and 42b are connected to the support plates 58a and 58b via the disc springs 64a and 64b, so that the press block bodies 40a and 40b are slightly different from each other. It can swing. For this reason, when the core pins 42a and 42b are firmly positioned and fixed to the pressing block bodies 40a and 40b without using the disc springs 64a and 64b, the positions of the core pins 42a and 42b and the through holes 74 are aligned. Otherwise, it is difficult for the core pins 42a and 42b to pass through the respective through holes 74, whereas in the present embodiment, for example, the second guide rails 26a and 26b are slightly worn and the core is punched. Even if the pins 42 a and 42 b are slightly inclined from the horizontal direction, the core pins 42 a and 42 b can easily pass through the through holes 74.

  That is, in the present embodiment, the core pins 42a, 42b and the through hole 74 of the upper die 18 are centered by supporting the core pins 42a, 42b so as to be swingable by the disc springs 64a, 64b. Like to do. Thereby, the clearance between the core pins 42a and 42b and the inner peripheral wall surface of the through hole 74 can be set with high accuracy.

  When the rods 36a and 36b reach the forward end position, the disc springs 64a and 64b are compressed. As a result, the one end surfaces of the large-diameter portions 56a and 56b are opposed to the bottom surfaces of the columnar recesses 57a and 57b on the support plates 58a and 58b with a very slight clearance.

  Through the above operation, the cavity 20 is formed inside the casting apparatus 10. Then, molten aluminum is supplied to the plurality of gates 22, and this molten metal is filled into the cavity 20 (step S4). At this time, the core pins 42a and 42b are cooled by a cooling medium such as air flowing through the cooling channels 50a and 50b. This cooling suppresses the thermal expansion of the core pins 42a and 42b and prevents the molten metal from adhering to the core pins 42a and 42b.

  After a predetermined time has elapsed, the molten metal is cooled and solidified, and the cylinder head 1 as a cast product is obtained. In step S5, the cylinders 34a and 34b are urged to move the rods 36a and 36b backward. At this time, as shown in FIG. 2, the pressing block bodies 40a and 40b are first retracted by about 10 mm and separated from the second sliding molds 16a and 16b.

  With this separation, the core pins 42 a and 42 b are displaced from the camshaft journal hole 6 in the cylinder head 1. In other words, the core pins 42 a and 42 b are released from the restraining force of the solidified cylinder head 1.

  After the core pins 42a and 42b are retracted, the rods 36a and 36b are further retracted in step S6. Finally, the guide rods 66a and 66b are engaged with the step portions of the stepped hole portions 68a and 68b, and the second sliding dies 16a and 16b are moved away from each other. As a result, the second sliding dies 16a and 16b are retracted from the cylinder head 1 and the core pins 42a and 42b are further retracted.

  At this time, since the core pins 42a and 42b are released from the restraining force of the cylinder head 1, the second sliding molds 16a and 16b can be easily retracted even with a small driving force. For this reason, it is not necessary to use a cylinder having a large driving force as the cylinders 34a, 34b, and both the cast pins 42a, 42b and the second sliding dies 16a, 16b can be advanced and retracted by the cylinders 34a, 34b. Therefore, the casting apparatus 10 can have a simple configuration. Moreover, there is an advantage that the capital investment for the casting apparatus 10 can be reduced.

  Next, after the upper mold 18 is raised in step S7, the mold opening is performed by the first sliding molds 14a and 14b being retracted under the action of the cylinders 28a and 28b in step S8, and the cylinder head 1 is moved. It can be taken out.

  Thus, in the present embodiment, after the upper mold 18 is clamped, the second sliding molds 16a and 16b are clamped. For this reason, it is not necessary to move the core pins 42a and 42b backward. Therefore, the time for casting the cylinder head 1 can be shortened, and thereby the manufacturing efficiency of the cylinder head 1 can be improved.

  Moreover, since the camshaft journal hole 6 is cast using the core pins 42a and 42b facing each other, workability is improved as compared with the prior art in which the camshaft journal hole 6 is formed by drilling in a later process. Is greatly improved. Moreover, there is an advantage that the efficiency of the manufacturing operation of the cylinder head 1 is improved.

  In the above-described embodiment, the first sliding molds 14a and 14b are opened after the upper mold 18 is lifted, but the upper parts are opened after the first sliding molds 14a and 14b are opened. Needless to say, the mold 18 may be raised.

It is a principal part schematic sectional drawing of a cylinder head. 1 is a schematic overall perspective view of a cylinder head casting apparatus according to the present embodiment. FIG. 3 is a plan view of a main part in a state where an upper mold is removed in the casting apparatus of FIG. 2. It is a principal part longitudinal cross-sectional view of the casting apparatus of FIG. It is principal part longitudinal cross-section explanatory drawing which shows the state by which the core pin which comprises the casting apparatus of FIGS. 2-4 was inserted in the through-hole of the upper mold | type. It is a cross-sectional explanatory drawing of the core pin which comprises the casting apparatus of FIGS. It is a flowchart explaining the casting operation | work by the said casting apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cylinder head 4a-4c, 5a, 5b ... Tapered hole 6 ... Camshaft journal hole 10 ... Casting apparatus 12 ... Lower mold | type 14a, 14b, 16a, 16b ... Sliding mold | type 18 ... Upper mold | type 20 ... Cavity 28a, 28b, 34a, 34b ... cylinders 30a, 30b, 36a, 36b ... rods 40a, 40b ... pressing block bodies 42a, 42b ... cast pins 56a, 56b ... large diameter parts 57a, 57b ... cylindrical recesses 58a, 58b ... support plate 60a, 60b ... Retaining plate 62a, 62b ... Spring accommodating chambers 64a, 64b ... Disc springs 66a, 66b ... Guide rods 68a, 68b ... Stepped holes 72a-72d ... Projections 74 ... Through holes

Claims (2)

A method of manufacturing a cylinder head having a camshaft journal hole by casting,
A step of clamping the mold by displacing a set of first sliding molds arranged at positions opposed to each other toward a positioning-fixed lower mold;
A step of clamping the mold by displacing an upper mold having a hole along the axial direction of the camshaft journal hole toward the lower mold; and
Position the swingable core pin by being passed through the bearing support, respectively, and facing each other along the axial direction of the camshaft journal hole in a state linked Rutotomoni clearance is formed the elastic member A pair of second sliding dies disposed on the lower die is displaced toward the lower die and clamped to form a cavity, and the cast pin and the upper die are swung to swing. Inserting the core pin into the hole while centering with the hole ;
Pouring molten metal into the cavity;
Cooling and solidifying the molten metal to obtain a cylinder head in which a camshaft journal hole is formed at a position corresponding to the core pin, and then retreating each core pin; and
A step of opening each mold by retreating the second sliding mold together with the core pin;
Opening each of the first sliding molds by retreating the mold;
A step of opening the mold by separating the upper mold from the lower mold;
A method of manufacturing a cylinder head, comprising: A cylinder head manufacturing apparatus having a cast pin for casting a camshaft journal hole of a cylinder head,
A lower mold with fixed positioning;
A set of first sliding molds facing each other and approaching or separating from the lower mold;
A set of second sliding molds that face each other at a position different from the first sliding mold and that move forward and backward along the axial direction of the camshaft journal hole;
A pair of cast pins that are supported in a swingable manner by passing through a bearing provided in each of the second sliding molds in a state where a clearance is formed ;
A resilient member that constantly urges and biases the cast pin supported by one of the second sliding molds toward the remaining second sliding mold that faces the other;
A drive mechanism capable of advancing and retracting each core pin in the axial direction and capable of advancing and retracting each second sliding mold in the axial direction;
An upper mold that forms a cavity with the lower mold, the set of the first sliding mold, and the set of the second sliding mold;
Equipped with a,
When inserting the core pin into the hole formed in the upper die at the time of mold clamping, the core is centered between the core pin and the hole by swinging the core pin. Head manufacturing equipment.

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