Electromagnetic self-locking driving mechanism of lifting table

Abstract

The utility model discloses a lifting table electromagnetic self-locking driving mechanism which comprises a machine shell (1), a worm gear (2) is arranged in the machine shell (1), a worm is arranged on one side of the worm gear (2), a motor (4) is arranged outside the machine shell (1), the output end of the motor (4) is connected with the worm, a driving shaft (5) rotationally connected with the machine shell (1) is arranged on the axis of the worm gear (2), and the motor (4) is a direct current motor (4). The winding of the motor (4) is connected in parallel with a normally closed relay (6); the relay (6) is connected in parallel with a capacitor (7); the number of the capacitors (7) is two, and the two capacitors (7) are connected in series to form a group and then are connected in parallel with the relay (6). The utility model has the advantages that the self-locking performance is not reduced, the cost is lower, and the silence can still be kept after being used for a longer time.

Description

TECHNICAL FIELD

[0001] The utility model belongs to lifting table drive mechanism field especially, it relates to a lifting table electromagnetic self -lock drive mechanism. BACKGROUND

[0002] The structure of the lifting table includes a support frame, a slidingly connected table board is arranged on the support frame, a drive mechanism of the table board is arranged on the support frame, the drive mechanism can change the height of the table board and better adapt to the needs of different people.

[0003] The existing drive mechanism includes a plastic casing, the casing is fixed with the support frame, a worm gear is arranged in the casing, a worm is arranged on one side of the worm gear, a motor with an output end connected with the worm is arranged outside the casing, a drive shaft rotatably connected with the casing is arranged on the axis of the worm gear, and the drive shaft is connected with the table board through a screw rod.

[0004] When adjusting the height of the table board, in order to overcome the inertia effect (especially when the table board is lowered) and stop the table board in time after the motor is powered off, a motor used on the drive mechanism is a self-locking motor, which has a brake inside.

[0005] In the use process, it is found that the self-locking performance of the motor is reduced due to the friction between the brake and the motor shaft, that is, the self-locking performance of the drive mechanism is reduced.

[0006] In addition, most of the load of the table board acts on the casing through the drive shaft, and the action point is between the lower end surface of the drive shaft and the casing, which is easy to produce friction noise. Utility model content

[0007] The utility model discloses a lifting table electromagnetic self-locking drive mechanism, which has the advantages of not reducing the self-locking performance, lower cost and maintaining silence after being used for a long time.

[0008] The utility model discloses a technical scheme: a lifting table electromagnetic self -locking drive mechanism, including the casing, be equipped with the worm wheel in the casing, one side of worm wheel is equipped with the worm, the outside of casing is equipped with the motor of output end connection worm, the axis of worm wheel is equipped with the drive shaft of rotation connection with casing, its characterized in that: the motor is direct current motor, and the winding of motor is in parallel with the normally closed relay.

[0009] In the aforementioned lifting table electromagnetic self -locking drive mechanism, the capacitor is connected in parallel with the relay.

[0010] In the aforementioned lifting table electromagnetic self -locking drive mechanism, the capacitor has two, and the two capacitors are connected in series into a group and then connected in parallel with the relay.

[0011] In the aforementioned lifting table electromagnetic self -locking drive mechanism, the inside bottom surface of the casing is provided with a lower positioning blind hole, the top of the casing is provided with an upper positioning through hole, the lower end of the drive shaft passes through the upper positioning through hole and enters the lower positioning blind hole, the lower end surface of the drive shaft is provided with a transverse through oil guide groove, and the side wall of the lower positioning blind hole is provided with an oil storage groove.

[0012] In the aforementioned lifting table electromagnetic self -locking drive mechanism, the graphite gasket is arranged on the lower side of the drive shaft in the lower positioning blind hole.

[0013] In the aforementioned lifting table electromagnetic self -locking drive mechanism, the graphite gasket is circular.

[0014] Compared with the prior art, the utility model is connected in parallel with the normally closed relay on the winding of the motor on the basis of the existing drive mechanism, when the motor is powered on, the relay is disconnected, the motor normally works to drive the table plate to lift, when the motor is powered off, the relay is closed, the winding forms a loop, an induced current is generated, the rotor obtains magnetic hysteresis force, the inertia of the rotor is offset and the rotating speed is rapidly reduced, the self -locking function of the television is realized, and the table plate can be stopped. Since the motor is self -locked by the magnetic force generated by the induced current, the motor is not self -locked by friction, basically no loss is generated, the self -locking performance of the motor is not reduced, that is, the self -locking performance of the drive mechanism is not reduced. Moreover, the cost of the added electronic element is lower than that of the brake band, and the cost is lower after the motor cancels the brake band, that is, the cost of the drive mechanism is lower.

[0015] In addition, the utility model also improves the structure between the casing and the drive shaft, sets up the oil guide groove at the bottom of the drive shaft, sets up the oil storage groove on the side wall of the lower positioning blind hole, when the drive shaft rotates, the lubricating oil in the oil storage groove can enter the lower end surface of the drive shaft through the oil guide groove for replenishment, avoids dryness and loses lubricating effect, and can still keep mute after using for a longer time.

[0016] To sum up, the utility model has the advantages of not reducing the self -locking performance, being lower in cost and keeping mute after using for a longer time. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural diagram of Example 1.

[0018] Figure 2 1 is a circuit diagram of Example 1.

[0019] Figure 3 This is a schematic diagram of the connection between the housing and the drive shaft in Example 2.

[0020] Figure 4 This is a bottom view of the drive shaft in Example 2.

[0021] Figure 5 Schematic top view of the lower positioning blind hole in Example 2.

[0022] Figure 6 This is a schematic diagram of the graphite gasket in Example 3.

[0023] The markings in the accompanying drawings are: 1-housing, 2-worm gear, 4-motor, 5-drive shaft, 6-relay, 7-capacitor, 8-lower positioning blind hole, 9-upper positioning through hole, 10-oil guide groove, 11-oil storage tank, 12-graphite gasket. DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0025] Example 1. An electromagnetic self-locking drive mechanism for a lifting table, such as Figure 1 and Figure 2 As shown, it includes a housing 1, a worm wheel 2 is provided in the housing 1, a worm is provided on one side of the worm wheel 2, a motor 4 with an output end connected to the worm is provided on the outside of the housing 1, and a drive shaft 5 is provided on the axis of the worm wheel 2 to be rotatably connected to the housing 1. Figure 2 As shown,

[0026] The motor 4 is a DC motor without an internal brake. A normally closed relay 6 is connected in parallel to the windings of the motor 4. Relay 6 is a power relay, and a capacitor 7 is connected in parallel to the relay 6. Two capacitors 7 are connected in series and then connected in parallel to the relay 6. The capacitors provide filtering and, when grounded, can resist electromagnetic interference.

[0027] The working principle of embodiment 1: when the motor 4 is powered on, the relay 6 is powered on and in the open state, the current passes through the motor 4, the motor works, drives the worm to rotate, the worm drives the drive shaft 5 to rotate through the worm gear 2, and the table board of the lifting table is lifted. When the motor 4 is powered off after completing the height adjustment of the table board, the relay 6 is powered off and in the closed state, so that the winding of the motor 4 forms a complete loop. After the motor 4 is powered off, the rotor continues to rotate by inertia, an induced current is generated on the winding, a hysteresis force is generated, the rotating shaft on the rotor stops rotating quickly, and the lifting action of the table board is quickly stopped.

[0028] In the lifting table motor, the gravity of the table board is converted into the rotating force of the worm gear 2, that is, the greater the rotating resistance of the worm gear, the stronger the self-locking force of the driving mechanism, and the worm rotating resistance torque can be amplified through the worm gear torque. According to tests, when the worm rotating resistance torque of the motor without an electromagnetic brake is 3 Nm, the driving mechanism realizes self-locking, and in embodiment 1, when the relay 6 is closed, the worm rotating resistance torque can reach 4 Nm, which meets the requirements. The table board of the lifting table is driven by a lead screw, and the lead screw thrust (N) = (2*π* motor output torque (N.M)*(0.95 transmission loss)) / lead screw pitch (M). In a lifting table with a lead screw pitch of 0.01 m, the worm rotating resistance is increased by 1 Nm, and the self-locking weight that the table board can bear is increased by about 60 kg.

[0029] Embodiment 2. On the basis of embodiment 1, the connection structure between the casing 1 and the drive shaft 5 is further improved, and the characteristics are as shown in Figure 3

[0030] The inner bottom surface of the casing 1 is provided with a lower positioning blind hole 8, the top of the casing 1 is provided with an upper positioning through hole 9, the lower end of the drive shaft 5 passes through the upper positioning through hole 9 and enters the lower positioning blind hole 8, the lower end surface of the drive shaft 5 is provided with a transversely penetrating oil guide groove 10 with a width of 1.5 mm and a depth of 1 mm, and the side wall of the lower positioning blind hole 8 is provided with an oil storage groove 11 with a lower end flush with the bottom surface of the lower positioning blind hole 8.

[0031] Add lubricating grease to the lower positioning blind hole 8, insert the drive shaft 5 into the lower positioning blind hole 8, most of the grease is pressed into the oil storage groove 11, and as the drive shaft 5 rotates back and forth and the grease at the lower end surface of the drive shaft 5 is consumed, the grease in the oil storage groove 11 enters the lower end surface of the drive shaft 5 through the oil guide groove 10 and is uniformly coated during the back-and-forth rotation of the drive shaft 5, avoiding noise.

[0032] ​In the embodiment 2, the graphite pad 12 is arranged in the lower side of the driving shaft 5 in the lower positioning blind hole 8, and the graphite pad 12 is a circular ring with a thickness of 1.5 mm.

[0033] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", etc. indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

Claims

1. An electromagnetic self-locking drive mechanism for a lifting table, comprising a housing (1), a worm gear (2) disposed within the housing (1), a worm being disposed on one side of the worm gear (2), a motor (4) having an output end connected to the worm being disposed outside the housing (1), a drive shaft (5) being disposed on the axis of the worm gear (2) and being rotatably connected to the housing (1), and characterized in that: The motor (4) is a DC motor (4), and a normally closed relay (6) is connected in parallel to the winding of the motor (4).

2. The electromagnetic self-locking drive mechanism for a lifting table according to claim 1, characterized in that: A capacitor (7) is connected in parallel to the relay (6).

3. The electromagnetic self-locking drive mechanism for a lifting table according to claim 2, characterized in that: There are two capacitors (7), which are connected in series to form a group and then connected in parallel to the relay (6).

4. The electromagnetic self-locking drive mechanism for a lifting table according to claim 1, characterized in that: A lower positioning blind hole (8) is provided on the inner bottom surface of the casing (1), an upper positioning through hole (9) is provided on the top of the casing (1), the lower end of the drive shaft (5) passes through the upper positioning through hole (9) and enters the lower positioning blind hole (8), a transversely penetrating oil guide groove (10) is provided on the lower end surface of the drive shaft (5), and an oil storage groove (11) is provided on the side wall of the lower positioning blind hole (8).

5. The electromagnetic self-locking drive mechanism for a lifting table according to claim 4, characterized in that: A graphite gasket (12) is arranged in the lower positioning blind hole (8) and is located on the lower side of the driving shaft (5).

6. The electromagnetic self-locking drive mechanism for a lifting table according to claim 5, characterized in that: The graphite gasket (12) is in the shape of a ring.

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