Casting water injection process and mold for front end cover of motor

Abstract

The invention relates to the technical field of casting processing, and discloses a casting water injection process and mold for a front end cover of a motor, and the process comprises the following steps: step 1, placing a water injection mechanism on a product mold, and enabling a liquid outlet of the water injection mechanism to be communicated with a cavity of the product mold; the water injection mechanism comprises a sprue bush; a water injection hole is formed in the center of the sprue bush; the bottom end of the water injection hole is a liquid outlet; an angle of 5-10 degrees is formed between the hole wall of the water injection hole and the axis of the water injection hole, and the end, with the smaller inner diameter, of the two ends of the water injection hole serves as the bottom end; 2, the melt is injected into a cavity of a product mold through a water injection hole; according to the invention, hole flaws can be effectively reduced, and higher casting molding quality is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of casting processing, and in particular to a casting water injection process and a mold for a front end cover of a motor. Background Art

[0002] The front end cover of the motor is an important part of the motor. It is located at one end of the motor and plays the role of fixing the bearing. It is also connected to other equipment. The front end cover is required to achieve good sealing performance and a certain mechanical strength during processing to ensure that the motor can work stably during operation. In actual processing, the front end cover is usually processed by casting process, which has low processing cost and can produce parts with complex geometric shapes, which can meet the molding requirements of the front end cover of the motor.

[0003] In the casting process, the water injection process (i.e., melt filling process) is a very critical step, which is directly related to the final molding quality of the product. Water injection (melt filling) refers to the processing step of filling the casting cavity with liquid metal. In the water injection process, there are many casting methods, such as centrifugal casting, die casting, gravity casting, etc. Among them, centrifugal casting and die casting both require the use of specific equipment, with high processing costs, good molding surface quality, and a narrow scope of application; gravity casting has a low processing cost and does not require the use of specific equipment, but the processing quality is unstable. At present, the motor end cover is often processed by gravity casting, and in the prior art, a variety of methods are used to stabilize the processing quality of gravity casting. For example, the patent scheme with publication number CN116037897B discloses an aluminum alloy ingot casting equipment and process, and a special casting tank is designed to complete casting in a negative pressure environment protected by inert gas, avoiding oxidation caused by the contact of metal liquid with air, and improving the surface quality of the ingot and the quality of the ingot structure. For another example, some existing automatic casting equipment has functions such as temperature maintenance or negative pressure, which can ensure the fluidity of the metal solution itself and thus stabilize the quality of the casting.

[0004] All of the above methods are designed from the perspective of maintaining the quality of the cast metal liquid. However, in actual work, it is found that based on these methods, the castings obtained are still prone to hole defects, and there is still much room for improvement in the quality of castings. Summary of the invention

[0005] The present invention aims to provide a casting water injection process and a mold for a front end cover of a motor, which can effectively reduce hole defects and achieve a higher casting molding quality.

[0006] To achieve the above objectives, the present invention provides the following basic solutions.

[0007] Solution 1

[0008] A casting and water injection process for a front end cover of a motor comprises the following steps:

[0009] Step 1, placing the water injection mechanism on the product mold so that the liquid outlet of the water injection mechanism is connected to the mold cavity of the product mold;

[0010] The water injection mechanism comprises a sprue sleeve; a water injection hole is provided at the center of the sprue sleeve; the bottom end of the water injection hole is the liquid outlet; the hole wall of the water injection hole is 5 to 10 degrees with its axis, and the end with the smaller inner diameter of the two ends of the water injection hole is the bottom end;

[0011] Step 2: Inject the melt into the cavity of the product mold through the water injection hole.

[0012] Furthermore, the water injection mechanism comprises a sprue sleeve; a water injection hole is provided at the center of the sprue sleeve; the bottom end of the water injection hole is the liquid outlet; the hole wall of the water injection hole is 5 to 10 degrees with its axis, and the end with a smaller inner diameter of the two ends of the water injection hole is the bottom end;

[0013] Further, in step 2, the melt is injected into the cavity of the product mold through the water injection hole.

[0014] Furthermore, the inner diameter of the bottom end of the water injection hole is

[0015] Furthermore, the inner diameter of the bottom end of the water injection hole is

[0016] Furthermore, the method further comprises step 3, wherein after the melt in the cavity solidifies, the upper mold of the product mold is lifted, so that the sprue is broken at the smallest inner diameter of the water injection hole, so as to facilitate the removal of the water injection mechanism.

[0017] Further, in step 1, the product mold is placed on a core rod; the core rod is located on the Z axis of the product mold cavity and is coaxial with the center hole of the product mold; the core rod includes a supporting section; a raised portion is provided at the center of the top surface of the supporting section; the raised portion is arc-shaped.

[0018] Furthermore, the protrusion is located below the water injection hole, and the top surface of the protrusion is 4 to 8 mm away from the bottom end surface of the water injection hole.

[0019] Furthermore, the ratio of the inner diameter of the bottom end of the water injection hole to the diameter of the bottom surface of the protrusion is 1.5-2.

[0020] Furthermore, the product mold is a motor end cover mold.

[0021] Solution 2

[0022] A mold for a casting water injection process of a front end cover of a motor comprises a water injection mechanism; the water injection mechanism comprises a sprue sleeve; a water injection hole is arranged at the center of the sprue sleeve; the bottom end of the water injection hole is a liquid outlet; the hole wall of the water injection hole is 5 to 10 degrees with its axis, and the end with a smaller inner diameter of the two ends of the water injection hole is the bottom end.

[0023] Furthermore, it also includes a core rod; the core rod includes a supporting section; a protrusion is provided at the center of the top surface of the supporting section; the protrusion is arc-shaped; the ratio of the inner diameter of the bottom end of the water injection hole to the bottom diameter of the protrusion is 1.5-2.

[0024] The working principle and advantages of the present invention are:

[0025] In order to solve the problem of easy hole defects in castings, this solution first discovered the key influencing factor in the casting process - the water injection method. In conventional solutions, the discussion on the hole defects in castings mostly focuses on the temperature control of the product mold / melt, the quality control of the mold cavity surface and the control of the casting speed, but does not pay attention to the "water injection" method of casting, especially the influence of the flow pattern of the melt during the water injection process on the quality of the casting. This solution pays attention to this point and discovers the defects in the conventional water injection method.

[0026] In conventional water injection methods, the water injection mold structure used is often multi-stage or includes multiple components to form a multi-stage structure. For example, the patent with publication number CN102029383B - Aluminum alloy wheel gravity casting mold and casting method thereof, discloses a thermos cup as an aluminum liquid injection mechanism, and the inner diameter of the water injection hole of its structure adopts a three-stage structure of upper large inner diameter - middle small inner diameter - lower large inner diameter. This is also the most common water injection structure in the existing gravity casting process. This structure can achieve a better gravity shrinkage compensation effect and realize the automatic injection of the melt. However, in our actual application, the quality of the castings processed by this method is not stable, the product qualification rate is not high, and it is very easy to produce defects such as shrinkage, holes, etc.; and the straight runner formed by it is inconvenient to remove, and it is easy to damage the product or the water injection structure body during removal, which greatly hinders the processing efficiency and easily causes cost losses.

[0027] After many practical analyses, we finally focused the cause of the defects on the water injection mold, and after multiple stages of structural debugging, we finally formed this plan. During the structural debugging process, we first made multiple adjustments to the structural composition and structural proportions based on the conventional gravity casting mold, as shown in the attached figure. Figure 2As shown, it shows the initial version of the scheme formed by us during debugging. In the initial version, we retained the overall structure of large inner diameter in the upper part, small inner diameter in the middle part, and large inner diameter in the lower part, and chose to optimize the inner diameter ratio and length ratio between the upper part, the middle part, and the lower part, and adopted a three-piece structure of a pouring cup, a filter screen, and a pouring sleeve, so that the melt flow rate can be controlled more finely. Compared with the above-mentioned public patent, the middle length of the initial version is longer and the inner diameter ratio between the upper part, the middle part, and the lower part is more balanced. The melt under the action of gravity accumulation can obtain a stable flow rate in the middle part before flowing down, and it is not easy to cause a torrent. In addition, with a core rod inserted into the water injection hole, slow flow and diversion are carried out to ensure that the melt fills the cavity. After this initial version was put into use, the product defects of the products produced were reduced by 80%, but there were still 20% of the defects that could not be eliminated - mainly including shrinkage and hole defects in the central area of ​​the product that could not be eliminated.

[0028] In response to this, we conducted multiple rounds of practical analysis again, and further focused the cause of the defect on the structure of the water injection hole; and made a breakthrough discovery that the structural design of "large inner diameter in the upper part-small inner diameter in the middle part-large inner diameter in the lower part" is precisely the cause of the defect. Because the channel connecting the water injection hole and the cavity is exactly the structure of "small inner diameter in the middle part-large inner diameter in the lower part", under this structure, the melt will be dispersed when entering the lower part through the middle part, and this fluid dispersion phenomenon will be more serious when entering the cavity, so that the melt cannot continuously and evenly fill the cavity, resulting in air entrainment and shrinkage defects in the product.

[0029] Based on this, we have made a subversive adjustment to the structure of the water injection hole, which is to form this scheme. This scheme no longer adopts a three-stage structure, but directly adopts a gate sleeve and a water injection hole with a specific slope as a water injection mechanism. In this scheme, the aperture of the water injection hole is larger at the top and smaller at the bottom, combined with the control of the aperture ratio (that is, the slope of the hole wall of the water injection hole is controlled so that the gate sleeve can accumulate gravity, ensure the fluidity of the melt, and more finely control the melt speed), thereby improving the water inlet method at the cavity. When the melt is injected into the cavity of the product mold through the water injection hole, it will converge into a concentrated liquid column. When injected into the cavity, compared with the dispersed liquid flow, the liquid column can more fully discharge the gas in the cavity without entraining air, which can effectively reduce hole defects and achieve a higher casting quality. Furthermore, the present structure can be used to quickly separate the sprue (as described in step 3) without damaging the product or the water injection mechanism, thereby ensuring that the product and the pouring system are properly molded, thereby helping to improve processing efficiency and reduce cost losses.

[0030] In addition, this solution also optimizes the core rod structure, adjusts the core rod position and structural dimensions, so that when the molten metal enters the cavity, it can be buffered by the core rod and enter the cavity evenly and fully, rather than being completely diverted as in the initial version (which can easily lead to complete dispersion of the fluid and cause shrinkage). And under this structure, the core rod is also easier to install and remove. In summary, after applying this solution, the remaining 20% ​​of defects can be further reduced to 2%, and the product qualification rate is increased from 80% to 98%. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of a casting water injection process and a product mold structure of a mold embodiment 1 for a motor front end cover of the present invention;

[0032] Figure 2 This is a schematic diagram of the water injection mechanism structure in the initial version of the plan;

[0033] Figure 3 A schematic diagram of a casting water injection process and a water injection method of a mold embodiment 1 for a front end cover of a motor according to the present invention;

[0034] Figure 4 It is a schematic diagram of a casting water injection process and a sprue sleeve structure of a second embodiment of a mold for a front end cover of a motor according to the present invention;

[0035] Figure 5 The present invention is a schematic diagram of a core rod structure of a second embodiment of a casting and water injection process and a mold for a front end cover of a motor. DETAILED DESCRIPTION

[0036] The following is a further detailed description through specific implementation methods:

[0037] The markings in the drawings of the specification include: gate sleeve 1, water injection hole 2, liquid outlet 201, support ring 202, core rod 3, support section 301, protrusion 302, product mold 4, center hole 401, cavity 402, gate cup 5, filter screen 6.

[0038] Embodiment 1

[0039] The embodiment is basically as shown in the attached Figure 3 As shown: A casting water injection process for a motor front end cover, comprising the following steps:

[0040] Step 1: Place the water injection mechanism on the product mold 4 so that the liquid outlet 201 of the water injection mechanism is connected to the mold cavity 402 of the product mold 4.

[0041] In this embodiment, Figure 1 As shown, the product mold 4 is a motor end cover mold. In addition, in practical applications, the product mold 4 can also be a mold for other plate cover parts, or a product mold 4 with a horizontal four-opening mold structure and an upper and lower mold structure.

[0042] Specifically, the water injection mechanism includes a sprue sleeve 1. A water injection hole 2 is provided at the center of the sprue sleeve 1; the bottom end of the water injection hole 2 is a liquid outlet 201; the hole wall of the water injection hole 2 is 5 to 10 degrees with its axis, and the end with a smaller inner diameter of the two ends of the water injection hole 2 is the bottom end; the inner diameter of the bottom end of the water injection hole 2 is In this embodiment, the hole wall of the water injection hole 2 is specifically 6° with its axis; the inner diameter of the bottom end of the water injection hole 2 is specifically Here, by selecting this size, the channel shape of the water injection hole 2 is optimal, and the tapered flow channel formed can effectively control the flow rate of the subsequent melt, prevent turbulence, and ensure that the melt can smoothly fill the product mold 4.

[0043] In this step, the product mold 4 is placed on the core rod 3; the core rod 3 is located on the Z axis of the mold cavity 402 of the product mold 4 and is coaxial with the center hole 401 of the product mold 4; the core rod 3 includes a support section 301; a protrusion 302 is provided at the center of the top surface of the support section 301; the protrusion 302 is arc-shaped. Specifically, the protrusion 302 is located below the water injection hole 2, and the top surface of the protrusion 302 is 4 to 8 mm away from the bottom end surface of the water injection hole 2. The ratio of the inner diameter of the bottom end of the water injection hole 2 to the bottom surface diameter of the protrusion 302 is 1.5 to 2. In this embodiment, the ratio of the inner diameter of the bottom end of the water injection hole 2 to the bottom surface diameter of the protrusion 302 is specifically 2.

[0044] With the above structure, the core rod 3 can be used as a supporting and positioning member to support the product mold 4 and relatively position the product mold 4; and can be used to form the hollow part in the casting. In particular, the subsequent core rod 3 can also play a certain diversion role (and at the same time ensure uniformity and sufficiency), control the flow rate and flow direction of the melt to a certain extent, reduce the formation of turbulence and bubbles, and thus improve the product quality. In addition, this scheme can further finely control the flow morphology of the melt by limiting the spacing size between the top surface of the protrusion 302 and the bottom end surface of the water injection hole 2 (i.e., limiting the slow flow position of the core rod 3), and limiting the ratio of the inner diameter of the bottom end of the water injection hole 2 to the bottom surface diameter of the protrusion 302 (i.e., limiting the flowable area when the melt is diverted). The core rod 3 arranged below the bottom end surface of the water injection hole 2 can reduce the impact of the melt when it enters the cavity 402, and the arc design of the protrusion 302 can evenly and stably disperse the melt to different areas of the cavity, reducing the problem of insufficient local filling. Furthermore, the layout of the core rod 2 at the outlet of the channel makes it easier to observe and adjust its position, reduces process variables, and makes it easier to remove the water injection mechanism and the core rod 2 later.

[0045] Step 2, injecting the melt into the cavity 402 of the product mold 4 through the water injection hole 2.

[0046] Here, when the melt enters the cavity 402 of the product mold 4 from the water injection hole 2, it will be converged into a concentrated water column through the structure of the water injection hole 2, and will be buffered and diverted to the cavity 402 of the product mold 4 by the protrusion 302 of the core rod 3; such a dynamic line setting helps to make the melt evenly and concentratedly diverted to the cavity 402, and evenly and fully fill the cavity 402, and it is not easy to produce hole defects; thereby achieving better casting performance.

[0047] Step 3, after the melt in the cavity 402 solidifies, lift the upper mold of the product mold 4 so that the sprue is broken at the smallest inner diameter of the water injection hole 2, so as to facilitate the removal of the water injection mechanism. The sprue is a pouring channel that directly leads to the cavity 402 of the product mold 4 when the melt enters the cavity 402 of the product mold 4, and is also the primary part of pressure transmission. Here, the sprue corresponds to the channel of the water injection hole 2.

[0048] In this arrangement, since the connection between the water injection mechanism and the cavity 402 of the product mold 4 is exactly the smallest inner diameter of the water injection hole 2, the section inertia moment here is small and easy to break, and no additional process is required to divide the runner. In addition, the breaking position will not cause damage to the processed product, and can also stabilize the optimal position for the melt to enter the cavity 402 of the product mold.

[0049] Specifically, after the water injection mechanism is removed, the excess melt (i.e. the remaining sprue) formed in the water injection hole 2 is pushed out of the water injection hole 2 from the bottom end surface of the water injection hole 2 to facilitate the next use.

[0050] This arrangement facilitates quick cleaning of residual melt in the water injection mechanism after each casting, and can timely prevent residual melt from contaminating new melt (if not cleaned in time, these residues will be mixed into fresh melt during the new casting process, resulting in inclusions in the casting, affecting the purity and mechanical properties of the casting), and ensure smooth pouring (if the pouring channel is blocked, the melt cannot smoothly enter the mold cavity, which may cause incomplete filling, pores, shrinkage holes and other problems, seriously affecting the quality of the casting), and can also reduce heat loss and ensure the thermal uniformity of the melt (residual metal in the sprue may absorb part of the heat of the new melt, causing the melt temperature to drop. Uneven temperature will affect the fluidity of the melt, and then affect the filling effect and final molding quality of the casting). However, the existing casting system cannot achieve the above effects, but only supports continuous pouring, and when it is necessary to clean the residual melt, it is difficult to clean and easy to damage the product and the pouring mechanism itself.

[0051] The present embodiment provides a casting and water injection process for a motor front end cover, which can effectively reduce hole defects and achieve a higher casting molding quality.

[0052] Embodiment 2

[0053] A mold for a casting and water injection process for a front end cover of a motor comprises a water injection mechanism and a core rod 3; and can be used to perform a casting and water injection process for a front end cover of a motor as described in the first embodiment.

[0054] Specifically, Figure 4 As shown, the water injection mechanism includes a sprue sleeve 1; a water injection hole 2 is provided at the center of the sprue sleeve 1; the bottom end of the water injection hole 2 is the liquid outlet 201; the hole wall of the water injection hole 2 is 5 to 10 degrees with its axis, and the end with the smaller inner diameter of the two ends of the water injection hole 2 is the bottom end. The inner diameter of the bottom end of the water injection hole 2 is A support ring 202 is provided around the outer surface of the sprue bushing 1 and can be used as a handle to facilitate the transportation and installation of the sprue bushing 1 .

[0055] like Figure 5 As shown, the core rod 3 includes a supporting section 301; a protrusion 302 is provided at the center of the top surface of the supporting section 301; the protrusion 302 is arc-shaped; the ratio of the inner diameter of the bottom end of the water injection hole 2 to the bottom diameter of the protrusion 302 is 1.5-2.

[0056] In specific applications, the casting water injection process for the motor front end cover described in Example 1 is used. The water injection mechanism is placed on the product mold 4, so that the liquid outlet 201 of the water injection mechanism is connected with the mold cavity 402 of the product mold 4; the product mold 4 is placed on the core rod 3; the core rod 3 is coaxial with the center hole 401 of the product mold 4. At this time, the protrusion 302 is located below the water injection hole 2, and the top surface of the protrusion 302 is 2 to 4 mm away from the bottom end surface of the water injection hole 2.

[0057] The mold for the casting water injection process of the motor front end cover provided in this embodiment eliminates the following Figure 2 The pouring cup 5 and filter screen 6 structure can complete the water injection process by only using the pouring sleeve 1 and the core rod 3. The overall structure is simple and easy to make and use. In addition, the application of this mold can effectively reduce hole defects and improve the casting quality.

[0058] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field are aware of all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement the scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for the ordinary technicians in the relevant field to implement this application. It should be pointed out that for the technicians in this field, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A casting water injection process for a motor front end cover, characterized in that: The following steps are involved: Step 1, placing the water injection mechanism on the product mold so that the liquid outlet of the water injection mechanism is connected to the mold cavity of the product mold; The water injection mechanism comprises a sprue sleeve; a water injection hole is provided at the center of the sprue sleeve; the bottom end of the water injection hole is the liquid outlet; the hole wall of the water injection hole is 5 to 10 degrees with its axis, and the end with the smaller inner diameter of the two ends of the water injection hole is the bottom end; Step 2: Inject the melt into the cavity of the product mold through the water injection hole.

2. A casting water injection process for a motor front end cover according to claim 1, characterized in that: The inner diameter of the bottom end of the water injection hole is 3. A casting water injection process for a motor front end cover according to claim 2, characterized in that: The inner diameter of the bottom end of the water injection hole is 4. The casting water injection process for the front end cover of the motor according to claim 1, characterized in that: The method further comprises step 3, wherein after the melt in the cavity solidifies, the upper mold of the product mold is lifted to break the sprue at the smallest inner diameter of the water injection hole, so as to facilitate the removal of the water injection mechanism.

5. The casting water injection process for the front end cover of the motor according to claim 1, characterized in that: In step 1, the product mold is placed on a core rod; the core rod is located on the Z axis of the product mold cavity and is coaxial with the center hole of the product mold; the core rod includes a supporting section; a raised portion is provided at the center of the top surface of the supporting section; the raised portion is arc-shaped.

6. A casting water injection process for a motor front end cover according to claim 5, characterized in that: The raised portion is located below the water injection hole, and the top surface of the raised portion is 4 to 8 mm away from the bottom end surface of the water injection hole.

7. The casting water injection process for the front end cover of the motor according to claim 5, characterized in that: The ratio of the inner diameter of the bottom end of the water injection hole to the bottom diameter of the protruding portion is 1.5-2.

8. The casting water injection process for the front end cover of a motor according to claim 1, characterized in that: The product mold is a motor end cover mold; and the product mold adopts a horizontal four-open mold structure or an upper and lower mold structure.

9. A mold for the casting and water injection process of the front end cover of a motor, characterized in that: It includes a water injection mechanism; the water injection mechanism includes a sprue sleeve; a water injection hole is provided at the center of the sprue sleeve; the bottom end of the water injection hole is the liquid outlet; the hole wall of the water injection hole is 5 to 10 degrees with its axis, and the end with a smaller inner diameter at both ends of the water injection hole is the bottom end.

10. The mold for the casting water injection process of the motor front end cover according to claim 9, characterized in that: It also includes a core rod; the core rod includes a supporting section; a convex portion is provided at the center of the top surface of the supporting section; the convex portion is arc-shaped; the ratio of the inner diameter of the bottom end of the water injection hole to the bottom diameter of the convex portion is 1.5-2.

Images