A power transmission structure of a household platform elevator

Abstract

The present invention discloses a power transmission structure of a household platform elevator, which is connected and linked with a driving motor and a driving nut. In particular, the power transmission structure includes a transmission belt, a first pulley and an offset shaft assembly, wherein the first pulley is keyed to the output shaft of the driving motor and rotates coaxially, and the offset shaft assembly is integrally mounted with a bearing seat, an offset shaft, an encoder and a second pulley based on an offset bottom plate, and the offset shaft and the output shaft of the driving motor are distributed on both sides of the driving nut and are axially parallel, and the transmission belt is sleeved on the first pulley and the second pulley for closed-loop rotation and the transmission belt is pressed against the two sides of the axial center symmetry of the driving nut to transmit power. The power transmission structure of the present invention is applied, and the pressing position of the transmission belt facing the driving nut is improved by adding an offset shaft assembly while ensuring power transmission, and the external force that causes the axial skewness of the driving nut is completely eliminated, which is beneficial to prolonging the service life and maintenance period of the driving nut, and improving the noise and physical sensation of elevator operation.

Description

Technical Field

[0001] The invention relates to a household platform elevator driven by a screw and a nut, and in particular to an improved power transmission structure of the household platform elevator, belonging to the technical field of electromechanical applications. Background Art

[0002] With the advancement of urbanization, people's living standards and construction technology have been continuously improved, and buildings of various heights have appeared around people in an endless stream. There are skyscrapers that soar into the sky, various commercial and transportation hub buildings that occupy a large area, and residential and office buildings with different numbers of floors and heights. Whether in appearance or interior decoration, they bring people a thriving social development experience. In many housing buildings, villas, nursing homes, and even subways, hospitals and other special passages, in order to solve the problem of inconvenience in going up and down stairs for the elderly or people with premature leg and foot failure, relatively small home elevators are often needed.

[0003] At present, home elevators are mainly traction-driven, hydraulic-driven and screw-nut-driven. Although traction-driven elevators dominate the market, they generally require a counterweight to balance the weight of the car, and additional car guide rails, counterweight guide rails and counterweight irons need to be arranged in the hoistway, resulting in a low car utilization rate. Therefore, for villas with relatively few floors, screw-nut-driven elevators are more practical.

[0004] With the increasing popularity of screw-nut driven elevators, the number of reported faults in their applications has also increased. After classification and summary, it was found that due to the offset of the drive motor and the traditional single-sided transmission design, the tensioning force (radial) of the drive belt on the nut is only biased to one side, and the contact pressure between the drive nut and the screw in the radial plane is unbalanced. Over time, the drive nut is prone to irreversible and increasingly severe wear and axial deflection, resulting in louder elevator operation noise and a shorter maintenance cycle. Summary of the invention

[0005] The purpose of the present invention is to propose a power transmission structure for a household platform elevator, which can efficiently transmit power to drive the elevator to move up and down while ensuring the axial stability of the drive nut and extending the maintenance period.

[0006] The technical solution for achieving the above-mentioned purpose in the present invention is a power transmission structure of a household platform elevator, which is connected and linked with a drive motor and a drive nut, wherein the drive motor is positioned and installed based on the elevator drive frame, and the drive nut is sleeved on the screw for controlled rotation, and is characterized in that: the power transmission structure includes a transmission belt, a first pulley and an offset shaft assembly, wherein the first pulley is keyed to the output shaft of the drive motor and rotates coaxially, and the offset shaft assembly is integrally installed with a bearing seat, an offset shaft, an encoder and a second pulley based on an offset base plate, the offset shaft and the output shaft of the drive motor are distributed on both sides of the drive nut and are axially parallel, the transmission belt is sleeved on the first pulley and the second pulley for closed-loop rotation, and the transmission belt is pressed against both sides of the axial center symmetry of the drive nut to transmit power.

[0007] The power transmission structure of the above-mentioned household platform elevator, further, the offset base plate in the offset shaft assembly and the bearing seat integrally installed therein are connected and fixed to the elevator drive frame, the offset shaft is connected to a pair of highly distributed ball bearings arranged in the bearing seat for axial positioning, the second pulley is keyed to the top of the offset shaft and rotates coaxially, and the encoder is sleeved on the bottom of the offset shaft to track the rotation speed.

[0008] The power transmission structure of the above-mentioned household platform elevator, further, the housing of the encoder is connected to the elevator drive frame radially to stop rotation through an S-shaped spring sheet, and has a flexible tracking space that conforms to the axial deflection and vibration of the offset shaft.

[0009] The power transmission structure of the above-mentioned household platform elevator, further, the driving nut is assembled as a whole with the elevator driving frame based on the driving base plate, and the driving base plate is equipped with one or more sets of tensioning wheel assemblies matching and abutting the transmission belt, and the transmission belt is pressed and gathered toward the coplanarity of the three axes on the side of the driving nut facing the offset axis, the side facing the output shaft of the driving motor or the side facing the two axes.

[0010] The power transmission structure of the above-mentioned household platform elevator, further, the two sets of tensioning wheel assemblies are arranged in a pair on the outside of the transmission belt on either side of the driving nut, and a self-aligning ball bearing is provided between the tensioning shaft and the tensioning outer wheel in each tensioning wheel assembly.

[0011] The power transmission structure of the above-mentioned household platform elevator, further, the transmission belt is a multi-V belt with a plurality of length-extending grooves on the inner side, and the circumferential outer surfaces of the first pulley, the second pulley and the driving nut are set as multi-V pulleys that match and mesh with the transmission belt.

[0012] The power transmission structure of the above-mentioned household platform elevator further comprises a brake for releasing and applying radial braking force on the top side of the driving nut, and the offset shaft assembly, the driving motor output shaft, the first pulley and the transmission belt are all stopped when the driving nut is in the braking state.

[0013] The power transmission structure of the above-mentioned household platform elevator, further, the brake is installed on a brake base plate with a brake body and an internal electromagnetic coil, a spring, and a brake disc with a friction plate, the inner annular surface of the brake disc is set as an internal spline, and the brake disc is connected and rotated synchronously through an external spline sleeve, a cross slider and a drive nut matched with the internal spline, and the electromagnetic coil overcomes the spring force when it is energized, and the brake disc floats on the brake base plate and rotates freely with the drive nut; when the electromagnetic coil is de-energized, the spring is tensioned, and the brake disc contacts and frictionally stops with the brake base plate.

[0014] The power transmission structure of the household platform elevator mentioned above further has a gap at the connection between the cross slider and the external spline sleeve that can be radially displaced and compensate for axial tilt.

[0015] The power transmission structure using the present invention has outstanding substantial characteristics and remarkable progress: the design improves the pressing position of the transmission belt facing the driving nut while ensuring power transmission by adding an offset shaft assembly, completely eliminating the external force that causes axial skewness of the driving nut, which is beneficial to improving the matching accuracy between the driving nut and the screw, reducing wear and extending the service life and maintenance period of the driving nut, and improving the noise and physical feel of elevator operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a three-dimensional structural schematic diagram from one perspective of the power transmission of the household platform elevator of the present invention.

[0017] Figure 2 It is a three-dimensional structural schematic diagram of the power transmission of the household platform elevator of the present invention from another perspective.

[0018] Figure 3 It is a vertical axial section schematic diagram of the power transmission structure of the present invention.

[0019] Figure 4 It is a horizontal cross-sectional schematic diagram of the power transmission structure of the present invention.

[0020] Figure 5 It is an axial cross-sectional schematic diagram of the tensioning wheel assembly in the power transmission structure of the present invention. DETAILED DESCRIPTION

[0021] The specific implementation modes of the present invention will be further described below in conjunction with the accompanying drawings of the embodiments, so that the technical solution of the present invention is easier to understand and grasp, thereby making a clearer definition of the protection scope of the present invention.

[0022] The designer of this invention aims at the practical shortcomings of existing home elevators, especially the home platform elevators used in single-family villas, which have unreasonable power transmission structures, causing the drive nut to wear too fast and the elevator to make obvious noise during operation, requiring regular maintenance. In view of this, after structural improvements, an innovative power transmission structure for home platform elevators is proposed, which, on the one hand, maintains a high power transmission efficiency from the drive motor to the drive nut, and on the other hand, keeps the drive nut aligned and coaxial with the screw to eliminate the deteriorating abnormal thread wear and the noise generated thereby.

[0023] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown in the structural overview of the preferred embodiment of the present invention, the power transmission structure of this kind of household platform elevator is connected and linked with the drive motor 1 and the drive nut 2, wherein the drive motor 1 is positioned and installed based on the elevator drive frame (a conventional necessary structure of this type of elevator, not shown), and the drive nut 2 is sleeved on the screw 3 and rotated by power transmission. The overview of the power transmission structure is: its structural composition mainly includes three parts: a transmission belt 41, a first pulley 42 and an offset shaft assembly 43, wherein the first pulley 42 is keyed to the output shaft of the drive motor 1 and rotates coaxially; the structure of the offset shaft assembly 43 is summarized as a bearing seat 431, an offset shaft 433, an encoder 435 and a second pulley 434 are integrally installed based on the offset bottom plate 82. As the main feature different from the traditional structure, the offset shaft 433 and the output shaft of the drive motor are distributed on both sides of the drive nut 2 and are axially parallel, and the transmission belt 41 is sleeved on the first pulley 42 and the second pulley 434 to rotate in a closed loop, and the transmission belt 41 is pressed against the two sides of the axial center symmetry of the drive nut 2 to transmit power. The winding effect of the transmission belt is as follows Figure 4 As shown in the close-up, if the offset shaft and the output shaft of the drive motor are arranged on the left and right sides of the drive nut, the area where the drive belt presses against the drive nut after being wound is the arc segments on the front and back sides. Since the tension force at each point along the entire length of the drive belt is uniform, compared with the traditional single-sided drive belt transmission, the drive belt of the power transmission structure of the present invention not only doubles the pressing effect on the drive nut, which is more conducive to power transmission, but also can make the external force that causes the axial skew of the drive nut relatively offset in the front and back directions. It can be seen that the improvement of the power transmission structure effectively overcomes the lateral pulling force on the drive nut of the traditional power transmission method, and fundamentally improves the stability of the drive nut receiving the axial rotation of the driving force.

[0024] From the further detailed features, first of all, the main function of the offset base plate 82 (simplified diagram) and the bearing seat integrally mounted therein in the offset shaft assembly is to axially position the offset shaft, thereby stabilizing the power transmission effect of the transmission belt. Therefore, the offset base plate and the bearing seat are both connected to the elevator drive frame, that is, they are equivalently fixed to the drive motor. The offset shaft 433 is axially positioned by passing through a pair of highly distributed ball bearings 432 provided in the bearing seat 431, and the second pulley 434 is keyed to the top of the offset shaft 433 and coaxially rotates with it, and provides closed-loop support for the transmission belt corresponding to the first pulley on the other side of the drive nut, thereby releasing the support function of the drive nut.

[0025] In order to improve the functionality of the offset shaft assembly, such as real-time monitoring of the speed of the transmission belt and in-depth sensing of the slippage or breakage of the transmission belt, the offset shaft assembly is optionally equipped with an encoder and sleeved on the bottom of the offset shaft to track the speed. Due to the working principle of the encoder, it is necessary to ensure that its body does not rotate, and the internal speed detection is measured by sleeved offset shaft with a rubber ring or silicone tube. The optional encoders are Changchun Yuheng's ZKT-D00, or Yike Electronics' EB100P, etc.

[0026] In the process of power transmission, although the above-mentioned offset shaft theoretically achieves axial positioning and axial retention, there is a tendency potential energy of yaw to a certain extent. In addition to not rotating, the encoder housing needs to have a corresponding extremely fine flexible tracking space, that is, the ability to absorb the above-mentioned tendency potential energy. Therefore, the encoder should avoid being directly rigidly mounted on the elevator drive frame. In the preferred embodiment shown in the figure, the housing of the encoder is connected to the elevator drive frame through an S-shaped spring sheet 83.

[0027] Furthermore, the driving nut 2 is integrally assembled with the elevator driving frame based on the driving base plate 81, and in order to improve the energy efficiency of the power transmission of the transmission belt, the bottom side of the driving base plate 81 can be customized to be equipped with one or more tensioning wheel assemblies (hereinafter referred to as assemblies) that match and abut the transmission belt, thereby realizing that the transmission belt is pressed against and gathered toward the coplanarity of the three axes on the side of the driving nut facing the offset axis, the side facing the output shaft of the driving motor, or the side facing the two axes. On the one hand, the tension of the transmission belt is improved, and on the other hand, it is also necessary to ensure that the force applied to the two sides of the driving nut is consistent. For this reason, in the illustrated embodiment, four sets of tensioning wheel assemblies are used, and two sets are arranged in pairs on the outer side of the transmission belt on both sides of the driving nut, that is, the assembly 44a and the assembly 44b are arranged in a pair on the side facing the offset axis, and the assembly 44c and the assembly 44d are arranged in a pair on the side facing the output shaft of the driving motor, and the winding shape of the transmission belt on both sides is a gourd shape with the driving nut as the base.

[0028] As a further optimization design, Figure 5In each tensioning wheel assembly 44 shown, a self-aligning ball bearing 443 is provided between the tensioning shaft 441 and the tensioning outer wheel 442. The self-aligning ball bearing ensures that the axial direction of the tensioning outer wheel is always parallel to the axial direction of the screw rod and the drive nut, thereby optimizing the transmission performance of the transmission belt facing the main drive nut.

[0029] In addition, the transmission belt is a poly-V belt (not specifically shown) with a plurality of grooves extending in length on the inner side, and the circumferential outer surfaces of the first pulley, the second pulley and the driving nut are set as poly-V pulleys that mesh with the transmission belt. The transmission assembly of the poly-V belt and the poly-V pulley is preferred here. On the one hand, under the matching meshing with sufficient tension strength, the transmission power facing each pulley and the driving nut is proportional to the number of tooth grooves, so the transmission energy efficiency can be reliably guaranteed; on the other hand, it can avoid the common synchronous belt (teeth and tooth grooves are both set in width) from misaligning teeth at the pulley and the driving nut due to tension and stretching, affecting the meshing transmission and shortening the service life of the transmission parts.

[0030] On the other hand, the top side of the driving nut 2 is provided with a brake 5 for releasing and applying radial braking force, and the offset shaft assembly 43, the output shaft of the driving motor 1, the first pulley 42 and the transmission belt 41 are all stopped when the driving nut is in the braking state. This improves the power transmission while also providing an overall linkage lock in the event of a system failure or power failure in the elevator.

[0031] The specific detailed structure for achieving the above-mentioned braking includes: the brake 5 is equipped with a brake body and an internal electromagnetic coil 52, a spring 53, and a brake disc 51 with a friction plate based on a brake base plate 84, the inner ring surface of the brake disc is set as an internal spline, and the brake disc is connected and rotated synchronously through an external spline sleeve 61 matched with the internal spline, a cross slider 62 and a driving nut 2. Referring to the figure, the brake disc 51 is a hollow sleeve and a disc surface integrally formed structural member, and the inner wall of the sleeve is provided with an internal spline, and the bottom surface of the disc surface is integrally formed with a high-resistance friction surface (refer to the brake disc of a vehicle brake). The electromagnetic coil 52 and the spring 53 are respectively embedded and positioned in the brake body, and the electromagnetic coil is externally connected to the circuit and is the only electronic control part, which is used to generate a strong magnetic field when powered and automatically dissipate the magnetic field when powered off; and the top of the spring is positioned and hung, and the bottom end is connected to the disc surface of the brake disc. In the assembled state, the spring has a pushing tension to push the brake disc away from the brake body. The external spline sleeve 61 is also a hollow sleeve, and its structural features mainly include the following two parts: on the one hand, the upper outer wall is provided with an external spline, which can be inserted into the brake disc and cooperate with the internal spline respectively; on the other hand, the lower part is connected and cooperated with the top rib of the cross slider. The cross slider 62 is similar to the above-mentioned external spline sleeve, and is connected with the external spline sleeve and the drive nut respectively as a transmission component connecting the upper and lower parts. After the overall assembly of the elevator is completed, the brake is integrally sleeved on the screw rod. When the electromagnetic coil is energized, it overcomes the spring force, attracts the brake disc to float on the brake base plate and rotate freely with the drive nut; when the electromagnetic coil is de-energized, the spring is tensioned, and the brake disc contacts and frictionally stops with the brake base plate. In actual application, the brake disc is only visually discernible within 0.5mm due to the traction of the electromagnetic coil and the spring, but the achieved braking effect meets the ideal expectation.

[0032] Of course, in practical use, the elevator platform often has load deviation, causing the platform base plate to tilt horizontally. In order to keep the drive nut and the screw in a good connection and fit, a gap is reserved at the connection between the cross slider and the external spline sleeve for radial displacement and compensation of axial tilt, thereby eliminating the possibility of transmitting eccentric external force to the drive nut through the brake.

[0033] From the above introduction to the scheme and detailed description of the embodiments of the power transmission structure of the present invention, it can be seen that it has outstanding substantial characteristics and remarkable progress: this design improves the pressing position of the transmission belt facing the drive nut while ensuring power transmission by adding an offset shaft assembly, completely eliminating the external force that causes axial skewness of the drive nut, which is beneficial to improving the matching accuracy between the drive nut and the screw, reducing wear and extending the service life and maintenance period of the drive nut, and improving the noise and physical feel of elevator operation.

[0034] In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solutions formed by equivalent replacement or equivalent transformation shall fall within the scope of protection required by the present invention.

Claims

1. A power transmission structure of a household platform elevator, which is connected and linked with a drive motor and a drive nut, wherein the drive motor is positioned and mounted based on the elevator drive frame, and the drive nut is sleeved on the screw rod and rotated in a controlled manner, characterized in that: The power transmission structure includes a transmission belt, a first pulley and an offset shaft assembly, wherein the first pulley is keyed to the output shaft of the driving motor and rotates coaxially, and the offset shaft assembly is integrally mounted with a bearing seat, an offset shaft, an encoder and a second pulley based on an offset bottom plate, and the offset shaft and the output shaft of the driving motor are distributed on both sides of the driving nut and are axially parallel, and the transmission belt is sleeved on the first pulley and the second pulley for closed-loop rotation, and the transmission belt is pressed and gathered toward the coplanarity of the three axes on the side of the driving nut facing the offset shaft, the side facing the output shaft of the driving motor or the side facing the two axes, and the transmission belt is pressed against the driving nut and transmits power to the two sides symmetrically to the center; The driving nut is integrally assembled with the elevator driving frame based on the driving base plate, and the driving base plate is equipped with one or more sets of tensioning wheel assemblies matching and abutting the transmission belt; the two sets of tensioning wheel assemblies form a pair and are arranged on the outer side of the transmission belt on either side of the driving nut, and a self-aligning ball bearing is arranged between the tensioning shaft and the tensioning outer wheel in each tensioning wheel assembly; The top side of the driving nut is provided with a brake for releasing and applying radial braking force, and the offset shaft assembly, the output shaft of the driving motor, the first pulley and the transmission belt are all stopped when the driving nut is in a braking state; the brake is mounted on a brake base plate and is provided with a brake body and an internally connected electromagnetic coil, a spring, and a brake disc with a friction plate, the inner annular surface of the brake disc is set as an internal spline, and the brake disc is connected and rotated synchronously through an external spline sleeve, a cross slider and a driving nut that are matched with the internal spline, and the electromagnetic coil overcomes the spring force when it is energized, and the brake disc floats on the brake base plate and rotates freely with the driving nut; when the electromagnetic coil is de-energized, the spring is tensioned, and the brake disc contacts and frictionally stops with the brake base plate.

2. The power transmission structure of the household platform elevator according to claim 1, characterized in that: The offset base plate and the bearing seat integrally installed therein in the offset shaft assembly are connected and fixed to the elevator drive frame. The offset shaft is connected to a pair of highly distributed ball bearings in the bearing seat for axial positioning. The second pulley is keyed to the top of the offset shaft and rotates coaxially, and the encoder is sleeved on the bottom of the offset shaft to track the rotation speed.

3. The power transmission structure of the household platform elevator according to claim 2 is characterized in that: The housing of the encoder is connected to the elevator driving frame through an S-shaped spring sheet to prevent radial rotation, and has a flexible tracking space that conforms to the axial deflection and shaking of the offset shaft.

4. The power transmission structure of the household platform elevator according to claim 1 is characterized in that: The transmission belt is a multi-V belt with a plurality of lengthwise extending grooves on the inner side surface, and the circumferential outer surfaces of the first pulley, the second pulley and the driving nut are configured as multi-V pulleys that match and mesh with the transmission belt.

5. The power transmission structure of the household platform elevator according to claim 1 is characterized in that: A gap is left at the connection between the cross slider and the external spline sleeve to enable radial displacement and compensate for axial tilt.

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