Hydraulic control loop for mold opening of injection molding machine

Abstract

The invention discloses a hydraulic control loop for mold opening of an injection molding machine, which comprises a pressure oil supply end, an oil tank and a mold locking oil cylinder, and is characterized by further comprising a mold opening slow valve, a mold opening fast valve, a mold closing valve, a mold opening valve, a mold closing oil return valve, a mold clamping safety valve and a mold clamping safety valve pilot valve, when the safety door of the injection molding machine is closed, the pilot valve of the mold opening valve is powered on, system pressure oil at the pressure oil supply end enters a rod cavity of the mold locking oil cylinder through the mold opening valve, oil returned from a rodless cavity of the mold locking oil cylinder sequentially passes through the mold opening quick valve and the mold opening slow valve and then returns to an oil tank, and the mold opening action is completed. Wherein the mold opening slow speed valve comprises a proportional direction valve; return oil of the mold opening action returns to the oil tank through the mold opening slow-speed valve, the brake position and the brake speed of the mold opening action are controlled by the proportional direction valve of the mold opening slow-speed valve, and the brake speed and the brake position can be adjusted by setting the opening size of the proportional direction valve of the mold opening slow-speed valve.

Description

Technical Field

[0001] The invention relates to the technical field of mold opening of an injection molding machine, and in particular to a hydraulic control circuit for mold opening of an injection molding machine. Background Art

[0002] Medium and large injection molding machines often use logic valves to control the mold opening and closing circuits due to the large system flow and the rated flow of solenoid valves and electro-hydraulic reversing valves. However, this method has several problems: 1. The mold opening repetition accuracy is insufficient, generally around ±2mm, which does not meet the precision requirements; 2. The logic valve control circuit is easily affected by oil temperature and lubrication, and the mold opening end position will fluctuate greatly; 3. If precise control is required, a proportional valve control will be installed, which will increase the cost; 4. If the mold weight changes, the braking distance can only be adjusted by changing the value of the last pump output, but the error is also relatively large. Summary of the invention

[0003] 1. Technical issues to be resolved The technical problem to be solved by the present invention is to provide a hydraulic control circuit for mold opening of an injection molding machine, wherein a mold opening slow valve is arranged on the oil return path of the mold opening, and the mold opening slow valve includes a proportional directional valve, and the speed and position during braking can be adjusted by setting the opening size of the proportional directional valve of the mold opening slow valve, thereby improving the mold opening repeatability accuracy, so that the repeatability accuracy is approximately within ±0.7mm, so as to avoid the increase of oil temperature or the influence of lubrication on the mold opening position.

[0004] (II) Technical solution The solution adopted by the present invention to solve the above technical problems is a hydraulic control circuit for mold opening of an injection molding machine, including a pressure oil supply end, an oil tank, a mold locking cylinder, and also includes a mold opening slow valve, a mold opening fast valve, a mold closing valve, a mold opening valve, a mold closing oil return valve, a mold clamping safety valve and a mold clamping safety valve pilot valve; when the injection molding machine safety door is closed, the pilot valve of the mold opening valve is energized, and the system pressure oil of the pressure oil supply end enters the rod chamber of the mold locking cylinder through the mold opening valve, and the return oil of the rodless chamber of the mold locking cylinder passes through the mold opening fast valve and the mold opening slow valve in turn back to the oil tank, completing the mold opening action; the mold closing valve, the mold clamping safety valve and the pilot valve of the mold clamping safety valve pilot valve are energized, and the system pressure oil of the pressure oil supply end enters the rodless chamber of the mold locking cylinder through the mold clamping safety valve pilot valve and the mold closing valve, and the return oil of the rod chamber of the mold locking cylinder passes through the mold closing oil return valve back to the oil tank, completing the mold closing action; Wherein, the mold opening slow valve includes a proportional directional valve; the return oil of the mold opening action returns to the oil tank through the mold opening slow valve, and the braking position and braking speed of the mold opening action are controlled by the proportional directional valve of the mold opening slow valve. The speed and position during braking can be adjusted by setting the opening size of the proportional directional valve of the mold opening slow valve.

[0005] In some embodiments, when the locking cylinder is performing rapid mold opening, the mold opening valve, the mold opening slow valve and the mold opening rapid valve are in an open state, and the return oil of the rodless chamber of the locking cylinder passes through the mold opening rapid valve and the mold opening slow valve in sequence back to the oil tank, completing rapid mold opening; when the locking cylinder is performing slow mold opening or braking, the mold opening rapid valve is in a closed state, the mold opening valve and the mold opening slow valve are in an open state, and the return oil of the rodless chamber of the locking cylinder passes through the mold opening slow valve back to the oil tank, completing slow mold opening or braking mold opening.

[0006] In some embodiments, when the locking cylinder is performing slow mold opening, the opening of the proportional directional valve of the mold opening slow valve is adjusted to become smaller to control the return oil amount of the rodless chamber of the locking cylinder to become less, so as to achieve slow mold opening of the locking cylinder; when the locking cylinder is braking, the opening of the proportional directional valve of the mold opening slow valve is closed to control the return oil amount of the rodless chamber of the locking cylinder to be 0, so as to achieve the braking action of the locking cylinder.

[0007] By adopting the above scheme, a mold opening slow valve is provided on the oil return path of the mold opening, and the mold opening slow valve includes a proportional directional valve. The speed and position during braking can be adjusted by setting the opening size of the proportional directional valve of the mold opening slow valve. The fast response of the proportional directional valve can improve the mold opening repeatability accuracy, so that the repeatability accuracy is approximately within ±0.7mm, so as to avoid the increase of oil temperature or the influence of lubrication on the mold opening position.

[0008] In some embodiments, a host computer is also included, and the host computer is used to adjust the opening size of the proportional directional valve of the mold opening slow valve.

[0009] In some embodiments, the host computer calculates the speed value and position value of the current mold opening action of the locking cylinder through an algorithm, compares the position value with the final brake position, and feeds back to the host computer; the host computer calculates an output voltage value for the proportional directional valve of the mold opening slow valve to adjust the opening size of the proportional directional valve of the mold opening slow valve to achieve repeated brake positions.

[0010] By adopting the above scheme, the host computer can adjust the output of the proportional directional valve to control the braking distance and the braking speed of the mold opening end point, so that consistency can be achieved for different molds.

[0011] (III) Beneficial effects Compared with the prior art, the present invention designs a hydraulic control circuit for mold opening of an injection molding machine. (1) The present invention provides a mold opening slow valve on the mold opening oil return path, and the mold opening slow valve includes a proportional directional valve. The speed and position of the brake can be adjusted by setting the opening size of the proportional directional valve of the mold opening slow valve. The proportional directional valve has a fast response, which can improve the mold opening repeatability accuracy, so that the repeatability accuracy is within about ±0.7 mm, so as to avoid the increase of oil temperature or the influence of lubrication on the mold opening position. (2) The host computer in the present invention can adjust the output of the proportional directional valve to control the braking distance at the mold opening end point and the braking speed of the mold opening, so that consistency can be achieved for different molds. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0013] Figure 1 The present invention is a schematic diagram of a hydraulic control circuit for opening a mold of an injection molding machine.

[0014] The corresponding component names of each figure mark in the figure are: 100, pressure oil supply end; 200, oil tank; 300, clamping cylinder; 301, rod chamber; 302, rodless chamber; 10, mold opening slow valve; 20, mold opening fast valve; 30, mold closing valve; 40, mold opening valve; 50, mold closing oil return valve; 60, mold clamping safety valve; 70, mold clamping safety valve pilot valve. DETAILED DESCRIPTION

[0015] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0016] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0017] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0018] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0019] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0020] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the examples can be practiced without these specific details.

[0021] The technical solutions provided by various embodiments of the present application are described below in conjunction with the accompanying drawings.

[0022] like Figure 1As shown, the present invention provides a hydraulic control circuit for mold opening of an injection molding machine, comprising a pressure oil supply end 100, an oil tank 200, a mold locking cylinder 300, and also comprising a mold opening slow valve 10, a mold opening fast valve 20, a mold closing valve 30, a mold opening valve 40, a mold closing oil return valve 50, a mold clamping safety valve 60 and a mold clamping safety valve pilot valve 70; when the injection molding machine safety door is closed, the pilot valve of the mold opening valve 40 is energized, and the system pressure oil of the pressure oil supply end 100 enters the rod chamber 301 of the mold locking cylinder 300 through the mold opening valve 40, and the return oil of the rodless chamber 302 of the mold locking cylinder 300 passes through the mold opening fast valve 20 and the mold opening slow valve 10 in turn and returns to the oil tank 200 to complete the mold opening action; the mold closing valve 30, the mold clamping safety valve 60, the mold opening valve 40, the mold closing oil return valve 50, the mold clamping safety valve 60 and the mold clamping safety valve pilot valve 70; when the injection molding machine safety door is closed, the pilot valve of the mold opening valve 40 is energized, and the system pressure oil of the pressure oil supply end 100 enters the rod chamber 301 of the mold locking cylinder 300 through the mold opening valve 40, and the return oil of the rodless chamber 302 of the mold locking cylinder 300 passes through the mold opening fast valve 20 and the mold opening slow valve 10 in turn and returns to the oil tank 200 to complete the mold opening action; 0 and the pilot valve of the mold clamping safety valve pilot valve 70 are energized, and the system pressure oil of the pressure oil supply end 100 enters the rodless chamber 302 of the clamping cylinder 300 through the mold clamping safety valve pilot valve 70 and the mold closing valve 30, and the return oil of the rod chamber 301 of the clamping cylinder 300 passes through the mold closing oil return valve 50 and returns to the oil tank 200 to complete the mold closing action; wherein, the mold opening slow valve 10 includes a proportional directional valve; the return oil of the mold opening action passes through the mold opening slow valve 10 and returns to the oil tank 200, and the braking position and braking speed of the mold opening action are controlled by the proportional directional valve of the mold opening slow valve 10, and the speed and position during braking can be adjusted by setting the opening size of the proportional directional valve of the mold opening slow valve 10. In some embodiments, when the locking cylinder 300 is performing rapid mold opening, the mold opening valve 40, the mold opening slow valve 10 and the mold opening rapid valve 20 are in an open state, and the return oil of the rodless chamber 302 of the locking cylinder 300 passes through the mold opening rapid valve 20 and the mold opening slow valve 10 in sequence to return to the oil tank 200, completing rapid mold opening; when the locking cylinder 300 is performing slow mold opening or braking, the mold opening rapid valve 20 is in a closed state, the mold opening valve 40 and the mold opening slow valve 10 are in an open state, and the return oil of the rodless chamber 302 of the locking cylinder 300 passes through the mold opening slow valve 10 to return to the oil tank 200, completing slow mold opening or braking mold opening. In some embodiments, when the locking cylinder 300 is performing slow mold opening, the opening of the proportional directional valve of the mold opening slow valve 10 is adjusted to be smaller to control the return oil amount of the rodless chamber 302 of the locking cylinder 300 to be reduced, so as to achieve slow mold opening of the locking cylinder 300; when the locking cylinder 300 is braking, the opening of the proportional directional valve of the mold opening slow valve 10 is closed to control the return oil amount of the rodless chamber 302 of the locking cylinder 300 to be 0, so as to achieve the braking action of the locking cylinder 300.By adopting the above scheme, a mold opening slow valve 10 is provided on the oil return path of the mold opening, and the mold opening slow valve 10 includes a proportional directional valve. The speed and position during braking can be adjusted by setting the opening size of the proportional directional valve of the mold opening slow valve 10. The fast response of the proportional directional valve can improve the mold opening repeatability accuracy, so that the repeatability accuracy is approximately within ±0.7mm, so as to avoid the increase of oil temperature or the influence of lubrication on the mold opening position.

[0023] In some embodiments, a host computer is also included, and the host computer is used to adjust the opening size of the proportional directional valve of the mold opening slow valve 10. In some embodiments, the host computer calculates the speed value and position value of the current mold opening action of the locking cylinder 300 through an algorithm, and compares the position value with the final brake position, and feeds back to the host computer; the host computer calculates an output voltage value for the proportional directional valve of the mold opening slow valve 10 to adjust the opening size of the proportional directional valve of the mold opening slow valve 10 to achieve repeated braking positions. With the above scheme, the host computer can adjust the output of the proportional directional valve to control the braking distance and the braking speed of the mold opening end point, so that consistency can be achieved for different molds.

[0024] The same and similar parts between the various embodiments in this specification can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0025] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A hydraulic control circuit for mold opening of an injection molding machine, comprising a pressure oil supply end (100), an oil tank (200), and a mold locking cylinder (300), characterized in that: The invention also comprises a mold opening slow valve (10), a mold opening fast valve (20), a mold closing valve (30), a mold opening valve (40), a mold closing oil return valve (50), a mold clamping safety valve (60) and a mold clamping safety valve pilot valve (70); when the injection molding machine safety door is closed, the pilot valve of the mold opening valve (40) is energized, the system pressure oil of the pressure oil supply end (100) passes through the mold opening valve (40) and enters the rod chamber (301) of the mold locking cylinder (300), and the return oil of the rodless chamber (302) of the mold locking cylinder (300) passes through the mold opening fast valve (20) and the opening valve (40) in sequence. The mold slow valve (10) returns to the oil tank (200), completing the mold opening action; the mold closing valve (30), the mold clamping safety valve (60) and the pilot valve of the mold clamping safety valve pilot valve (70) are energized, and the system pressure oil at the pressure oil supply end (100) passes through the mold clamping safety valve pilot valve (70) and the mold closing valve (30) into the rodless chamber (302) of the mold locking cylinder (300), and the return oil of the rod chamber (301) of the mold locking cylinder (300) passes through the mold closing oil return valve (50) and returns to the oil tank (200), completing the mold closing action; The mold opening slow valve (10) includes a proportional directional valve; the return oil of the mold opening action passes through the mold opening slow valve (10) and returns to the oil tank (200); the braking position and braking speed of the mold opening action are controlled by the proportional directional valve of the mold opening slow valve (10); and the speed and position during braking can be adjusted by setting the opening size of the proportional directional valve of the mold opening slow valve (10).

2. The hydraulic control circuit for mold opening of an injection molding machine according to claim 1, characterized in that: When the mold locking cylinder (300) is in a rapid mold opening state, the mold opening valve (40), the mold opening slow valve (10) and the mold opening fast valve (20) are in an open state, and the return oil of the rodless chamber (302) of the mold locking cylinder (300) passes through the mold opening fast valve (20) and the mold opening slow valve (10) in sequence and returns to the oil tank (200), thereby completing the rapid mold opening; when the mold locking cylinder (300) is in a slow mold opening or braking state, the mold opening fast valve (20) is in a closed state, the mold opening valve (40) and the mold opening slow valve (10) are in an open state, and the return oil of the rodless chamber (302) of the mold locking cylinder (300) passes through the mold opening slow valve (10) and returns to the oil tank (200), thereby completing the slow mold opening or braking mold opening.

3. The hydraulic control circuit for mold opening of an injection molding machine according to claim 2, characterized in that: When the mold locking cylinder (300) is performing slow mold opening, the opening of the proportional directional valve of the mold opening slow valve (10) is adjusted to be smaller to control the return oil volume of the rodless chamber (302) of the mold locking cylinder (300) to be reduced, so as to achieve slow mold opening of the mold locking cylinder (300); when the mold locking cylinder (300) is braking, the opening of the proportional directional valve of the mold opening slow valve (10) is closed to control the return oil volume of the rodless chamber (302) of the mold locking cylinder (300) to be 0, so as to achieve the braking action of the mold locking cylinder (300).

4. The hydraulic control circuit for mold opening of an injection molding machine according to claim 1, characterized in that: It also includes a host computer, which is used to adjust the opening size of the proportional directional valve of the mold opening slow valve (10).

5. The hydraulic control circuit for mold opening of an injection molding machine according to claim 4, characterized in that: The host computer calculates the speed value and position value of the current mold opening action of the locking cylinder (300) through an algorithm, compares the position value with the final brake position, and feeds back to the host computer; the host computer calculates an output voltage value for the proportional directional valve of the mold opening slow valve (10) to adjust the opening size of the proportional directional valve of the mold opening slow valve (10) to achieve the repeated position of the brake.

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