Dual-motor tandem type direct-drive electric ejection structure

Abstract

A double-motor tandem type direct-drive electric ejection structure comprises a lead screw and two drive motors, and is characterized in that the two drive motors are connected in series and include the first motor and the second motor, the first motor, the second motor and the lead screw are coaxially arranged, the front end of the first motor is connected with the rear end of the lead screw, and the rear end of the second motor is connected with the rear end of the lead screw. The rear end of the first motor is connected with the front end of the second motor through an injection coupling, and the front end of the lead screw is fixedly connected with the screw assembly. The structure design is simpler and more reasonable, the injection structure stability is good, the response speed is high, and the injection precision is higher.

Description

Technical Field

[0001] The present invention relates to the technical field of injection molding machines, and in particular to a dual-motor series direct-drive electric injection structure. Background Art

[0002] With the increasing development of industrial technology, the application fields of plastic products are becoming wider and wider, and the injection precision of injection molding machines for plastic products is becoming higher and higher. The injection structure plays a great role in controlling the injection precision.

[0003] The injection structure of the existing injection molding machine includes an injection motor and an injection screw mounted on the frame. The injection motor is generally a single motor, and the injection action is driven by a single motor. The motor is connected to the screw structure through a synchronous belt. The existing structure has the following defects during use:

[0004] 1. The injection action is driven by a single motor, which requires high power and is not suitable for high-load scenarios;

[0005] 2. The synchronous belt drive has backlash problems, there are intermediate transmission errors, the system's dynamic response speed is slow, and the transmission efficiency is low;

[0006] 3. Complex structure and loud noise.

[0007] Often, the existing Chinese patent number CN202323130613.0, "A Bidirectional Screw Injection Structure," includes a bidirectional screw and a drive motor. The bidirectional screw is formed with two front and rear sections of threads with different rotation directions. Two screw nuts are screwed onto the two sections of threads respectively. There are two drive motors, of which the first screw nut on the front is connected to the first motor in a transmission connection, and the second screw nut on the rear is connected to the second motor in a transmission connection. The front end of the bidirectional screw is fixedly connected to the screw assembly via a coupling. This structure uses a dual-motor drive, which reduces the power required by the servo motor, making the injection structure more stable and the injection accuracy higher. However, the motor is also connected to the drive screw through a synchronous belt, which will also cause intermediate transmission errors, affecting the injection accuracy. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a dual-motor series direct-drive electric injection structure with a simple and reasonable structure, fast response speed and high injection precision in response to the above-mentioned technical status quo.

[0009] The technical solution adopted by the present invention to solve the above technical problems is as follows: A double-motor series direct-drive electric injection structure, including a lead screw and a driving motor, is characterized in that: there are two series-connected driving motors, namely a first motor and a second motor, and the first motor, the second motor and the lead screw are coaxially arranged, wherein the front end of the first motor is connected to the rear end of the lead screw, the rear end of the first motor is connected to the front end of the second motor through an injection coupling, and the front end of the lead screw is fixedly connected to a screw rod assembly.

[0010] As an improvement, the connection structure between the first motor and the lead screw is: involute spline teeth are provided on the inner rotor of the first motor, and corresponding splines are formed at the rear end of the lead screw. The first motor is connected to the lead screw through the cooperation of the spline teeth and the splines.

[0011] Furthermore, the front end of the lead screw is connected to the screw rod assembly through a screw rod buckle.

[0012] Furthermore, two encoders are installed at the tail of the second motor to measure the rotational speed parameters of the first motor and the second motor respectively.

[0013] Furthermore, the lead screw is a ball screw, the lead screw is installed in an injection frame, a lead screw nut is sleeved outside the lead screw, and a force measuring sensor is installed on the injection frame.

[0014] Furthermore, a front flange and a rear flange are respectively installed at the front and rear ends of the injection frame.

[0015] Finally, the first motor is installed on the rear flange, and the front flange is connected to a water-cooled flange.

[0016] Compared with the prior art, the advantages of the present invention are as follows: Double-motor drive is adopted, the synchronous belt structure is cancelled, and the motor directly drives the lead screw structure. The direct drive of the motor avoids the backlash problem of intermediate transmission devices such as belts, significantly improves the positioning accuracy of the system, can achieve fast start and stop and high-speed movement, and has higher transmission efficiency; The two motors work together, and the output torque and power are superimposed, which is suitable for high-load scenarios; The two motors share the load, reduce the burden on a single motor, and extend the service life; The double-motor drive reduces the power required by the servo motor to overcome the limitations caused by the current servo motor technology, and at the same time relaxes the selection of the driver, reducing costs; The double-motor drive structure has high flexibility and can adjust the working modes of the two motors according to needs. The structure design of the present invention is simpler and more reasonable, the injection structure has good stability, fast response speed and higher injection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a cross-sectional view of an embodiment of the present invention;

[0018] Figure 2 It is a cross-sectional view of the motor joint part;

[0019] Figure 3 It is a sectional view of the spline part of the motor. Specific Embodiments

[0020] The present invention will be further described in detail below in conjunction with the embodiments with reference to the drawings.

[0021] As Figure 1 shown, a double-motor series-connected direct drive electric injection structure includes a lead screw 1 and drive motors. There are two series-connected drive motors, namely a first motor 2 and a second motor 3. Moreover, the first motor 2, the second motor 3 and the lead screw 1 are coaxially arranged. The front end of the first motor 2 is connected to the rear end of the lead screw 1, and the rear end of the first motor 2 is connected to the front end of the second motor 3 through an injection coupling 4. The front end of the lead screw 1 is fixedly connected to a screw rod 9 assembly.

[0022] The specific structure is as follows: The connection structure between the first motor 2 and the lead screw 1 is that involute spline teeth 22 are provided on the inner rotor 21 of the first motor 2, and corresponding splines 11 are formed at the rear end of the lead screw 1. The first motor 2 is connected to the lead screw 1 through the cooperation of the spline teeth 22 and the splines 11. The front end of the lead screw 1 is connected to the screw rod assembly 9 through a screw rod buckle 10. Two encoders are installed at the tail of the second motor 3 to measure the rotational speed parameters of the first motor and the second motor respectively. The lead screw 1 is a ball screw, the lead screw 1 is installed in an injection frame 5, a lead screw nut 30 is sleeved outside the lead screw 1, and a force sensor 6 is installed on the injection frame 5. Front flanges 7 and rear flanges 8 are respectively installed at the front and rear ends of the injection frame 5. The first motor 2 is installed on the rear flange 8, and the front flange 7 is connected to a water-cooled flange 20.

[0023] The working principle is:

[0024] The first motor 2 and the second motor 3 are connected in series through an injection coupling 4. Two encoders are installed at the tail of the second motor 3. The first motor 2 is connected to the lead screw spline 11 through the involute spline teeth on the inner rotor, so as to drive the ball screw 1 to rotate to complete the required injection action. The other side of the lead screw 1 is connected to the screw rod assembly 9 through a screw rod buckle 10.

[0025] Set conditions:

[0026] Let r1 be the rotational speed of the first motor, r2 be the rotational speed of the second motor, T1 be the torque of the first motor, T2 be the torque of the second motor, R be the rotational speed of the lead screw, V be the linear velocity of the lead screw, L be the lead of the lead screw, T be the torque of the lead screw, and η be the transmission efficiency

[0027] Then:

[0028] R = (r1 + r2) / 2 Unit: rpm / min

[0029] V = L*R / 60 Unit: mm / s

[0030] T = (T1 + T2) * η Unit: Nm.

[0031] The difference between the present invention and the prior art lies in:

[0032] 1. The injection action is driven by two motors. While a general motor uses a single motor.

[0033] 2. The injection motor directly drives the lead screw structure. While a general motor is connected through a timing belt.

[0034] Direct drive of the motor avoids the backlash problem of intermediate transmission devices such as belts, significantly improving the positioning accuracy of the system.

[0035] Due to the absence of intermediate transmission errors, the repeat positioning accuracy of the system is higher.

[0036] Direct drive reduces the inertia of transmission components, and the dynamic response speed of the system is faster.

[0037] The motor directly drives the lead screw, enabling fast start-stop and high-speed movement.

[0038] Direct drive reduces the energy loss of intermediate transmission devices, and the transmission efficiency is higher.

[0039] Direct drive simplifies the mechanical structure, reduces the failure points, and makes installation and maintenance more convenient.

[0040] Low noise and small vibration.

[0041] However, the design and control complexity of direct drive are also relatively high, requiring the realization of control requirements for high precision and dynamic response, the real-time processing of high-resolution feedback signals, and the design and implementation of complex control algorithms.

[0042] The advantages of the present invention are as follows:

[0043] 1. Two motors work together, and the output torque and power are superimposed, suitable for high-load scenarios;

[0044] 2. Two motors share the load, reducing the burden on a single motor and extending its service life;

[0045] 3. The two-motor drive structure reduces the power required by the servo motor to overcome the limitations caused by the current servo motor technology;

[0046] 4. The two-motor drive structure has high flexibility and can adjust the working modes of the two motors according to requirements.

[0047] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A double-motor series-connected direct-drive electric injection structure, comprising a lead screw and a driving motor, characterized in that: The driving motors are two in series, namely a first motor and a second motor, and the first motor, the second motor and the lead screw are coaxially arranged, wherein the front end of the first motor is connected to the rear end of the lead screw, the rear end of the first motor is connected to the front end of the second motor through an injection coupling, and the front end of the lead screw is fixedly connected to the screw rod assembly.

2. The dual-motor series-connected direct-drive electric injection structure according to claim 1, wherein: The connection structure between the first motor and the lead screw is as follows: involute spline teeth are provided on the inner rotor of the first motor, and corresponding splines are formed at the rear end of the lead screw. The first motor is connected to the lead screw through the cooperation of the spline teeth and the splines.

3. The dual-motor series-connected direct-drive electric injection structure according to claim 1, wherein: The front end of the lead screw is connected to the screw rod assembly through a screw rod buckle.

4. The dual-motor series-connected direct-drive electric injection structure according to claim 1, wherein: Two encoders are installed at the tail of the second motor to measure the rotational speed parameters of the first motor and the second motor respectively.

5. The dual-motor series-connected direct-drive electric injection structure according to any one of claims 1 to 4, characterized in that: The lead screw is a ball screw, the lead screw is installed in the injection rack, a lead screw nut is sleeved outside the lead screw, and a force measuring sensor is installed on the injection rack.

6. The dual-motor series-connected direct drive electric injection structure according to claim 5, wherein: Front flanges and rear flanges are respectively installed at the front and rear ends of the injection rack.

7. The dual-motor series-connected direct-drive electric injection structure according to claim 6, wherein: The first motor is installed on the rear flange.

8. The dual-motor series-connected direct-drive electric injection structure according to claim 7, characterized in that: The front flange is connected to the water-cooled flange.

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