Split-type mold for wheel casting

Abstract

The invention provides a split-type mold for wheel casting, the mold having an upper die, a split-type water-cooling side die and a lower die, and the split-type water-cooling side die is divided into four pieces along a circumferential direction of the wheel mold. A thermal deformation arc compensation surface is machined on arc portion of each split-type water-cooling lower side die, and a compensation surface is machined on key portions of 45-degree matching surfaces of adjacent split-type water-cooling upper side dies. The side die can effectively solve the problems such as untight matching between the matching surfaces, flashes of the matching surfaces and aluminum sticking and the like due to the thermal deformation and non-homogeneous expansion and shrinkage of the two portions of the split-type water-cooling side die.

Claims

1. A split-type mold for wheel casting, the mold comprising: an upper die, a split-type water-cooling side die and a lower die, the split-type water-cooling side die being divided into four pieces along a circumferential direction of a wheel mold, and further comprising: a thermal deformation arc compensation surface having points B, C as end points and passing through point E is machined on arc matching surface of a lower side die of each split-type water-cooling side die, that is an arc surface matched with a side wall of the lower die; a distance from the point E on the thermal deformation arc compensation surface to a point F on an original arc is 0.2 mm to 0.5 mm; and the points B, C are located on the original arc and respectively have a distance of 60 mm to 80 mm to a 45-degree matching surface; compensation surfaces are machined on key portions of 45-degree matching surfaces of adjacent split-type upper side dies, that is matching surfaces of four side dies, such that V-gaps are formed on the 45-degree matching surfaces of the side dies in a cold state when adjacent split-type upper side dies are matched, with a gap clearance of 0.2 mm to 0 4 mm on the side die inner circumference, and there is no gap on the side die inner circumference when 45-degree matching surfaces of split-type lower side dies, i.e. matching surfaces of four side dies, are in a matching state.

2. The mold according to claim 1, wherein the distance from the point E to the point F is 0.2 mm.

3. The mold according to claim 1, wherein the gap clearance on the side die inner circumference is 0.3 mm when the 45-degree matching surfaces of the split-type upper side dies are in a matching state.

4. The mold according to claim 1, wherein the range of the V-gap on the 45-degree matching surface of the spit-type upper side die is located between points I and J, wherein a point I is a parting surface of the spit-type upper side die and the spit-type lower side die, and the point J is a tangent point between a 9-degree slope of a hub inner rim and an arc.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The embodiments of the present invention can be described in details in conjunction with the accompanying drawings, wherein:

(2) FIG. 1 illustrates the matching form of side dies of the low-pressure casting wheel mold in the prior art, in which 1upper die, 2upper side die, 3lower side die, and 4lower die;

(3) FIG. 2 is a schematic of side die matching in the prior art;

(4) FIG. 3 is a schematic of a thermal deformation compensation surface at arc matching portions of the split-type water-cooling lower side die in the present invention;

(5) FIG. 4 is a schematic of a thermal deformation matching of 45-degree matching surface of split-type upper side dies;

(6) FIG. 5 is a schematic of a thermal deformation matching of 45-degree matching surfaces of split-type lower side dies.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiment 1: Mold Manufacturing

(7) On the premise of not influencing the casting process and complying with mold thermal deformation laws, thermal deformation compensation amounts on the arc side matching surfaces between the side dies and between the side die and the lower die are properly set.

(8) I. As shown in FIG. 3, five points A, B, F, C and D are concyclic (arc line before improvement); three points B, E and C are concyclic as the thermal deformation compensation portions; two points E and F have the maximum distance of 0.2 mm; being closer to the points B and C, a distance between two arcs is gradually smaller until the arcs are intersected); the points A, B, E, C and D form the improved arc line; the points B and C are located on an original arc, and 60 mm away from a 45-degree matching surface, respectively;

(9) II. No thermal deformation compensation amount is left for the 45-degree matching surface of the split-type water-cooling lower side die, while a thermal deformation compensation amount of 0.3 mm is used for the 45-degree matching surface of the split-type upper side die (non-water-cooling portion) to achieve a precise matching in the hot state;

(10) III. Programmed milling is performed on the thermal compensation arc surface formed by the points B, E and C on arc of split-type water-cooling lower side die; for the thermal compensation portion of the gap at the 45-degree matching surface of the split-type upper side die, the rotation angle of 45-degree matching surface is calculated according to the compensation amount, and gradual milling is performed within the range between I and J in the key portions of the 45-degree matching surface.

(11) The above mold is referred to as test group 1. In addition, molds are also obtained by being machined under the following parameters:

(12) test group 2: the point E on the thermal deformation arc compensation surface and the point F on the original arc have a distance of 0.2 mm; the points B, C are located on the original arc, and 60 mm away from the 45-degree matching surface, respectively; a gap clearance in the side die inner circumference is 0.2 mm;

(13) test group 3: the point E on the thermal deformation arc compensation surface and the point F on the original arc have a distance of 0.5 mm; the points B, C are located on the original arc, and 80 mm away from the 45-degree matching surface, respectively; a gap clearance in the side die inner circumference is 0.4 mm;

(14) test group 4: the point E on the thermal deformation arc compensation surface and the point F on the original arc have a distance of 0.4 mm; the points B, C are located on the original arc, and 70 mm away from the 45-degree matching surface, respectively; a gap clearance in the side die inner circumference is 0.3 mm;

(15) control group: the casting mold of the conventional aluminum wheel integrated side die, which is distinguished from the test group 1 in that it does not include the thermal deformation compensation portion.

Embodiment 2: Pilot Scale Test

(16) The mold manufactured in the method of Embodiment 1 is used for a casting test of A356 aluminum alloy hub under the normal operating conditions of the mold (aluminum liquid of 700 Celsius degrees, and the mold temperature is remained at the normal temperature field). The results show that in the casting tests concerning 5,000 pieces, the proportion of matching surface flashing of the castings is decreased from 100% to 2%, and the proportion of aluminum-sticking is decreased from 70% to 0.5%.

(17) At the same time, a life test is performed to the mold in the same method. The test proves that the life of the mold is improved from 20,000 pieces to 35,000 pieces; in overall consideration of the loss of the flashing, improvement of the life of the mold, stability of the on-site production takt, the cost for casting every 10,000 pieces of hubs is saved by 29300 CN Yuan.

(18) Tests are also performed on test groups 2-4. The results show that the proportion of matching surface flashing of the castings is decreased below 5%, the aluminum-sticking proportion is decreased below 0.9%, and the life of the mold is increased above 32,000 pieces. The molds of the above test groups greatly reduce the hub production cost, and bring in good economic and social benefits.