Description:Field of the Invention

The present invention relates generally to the field of sliding door mechanism in vehicles. More particularly, the present invention relates to a back drivable sliding door motor based-operating device employing a gear and pulley mechanism.
Background

Conventionally, hydraulic doors use hydraulic pistons to actuate opening and closing of vehicle door. Hydraulic pistons are operated by an operating system comprising of various types of valves, pressure monitoring mechanism and a hydraulic fluid tank. The operating system is bulky and occupies a lot of space. Further, the operating mechanism in hydraulic piston requires power to operate the hydraulic piston. In the absence of power, the piston locks in a particular place causing failure of movement of the door.

Further, in order to save space in vehicles such as minivans, buses, trailer cars, trains etc., gear/pulley based sliding doors are used. Typically, in such sliding doors, the operating mechanism involves a set of rollers and a gear system that moves the sliding door along a track, allowing it to open and close. Also, in such sliding door mechanisms, motor is connected to a drum with a cable wrapped around the drum. One end of the cable is used to open the sliding door and the other end of the cable is used to close the sliding door. In the event the vehicle is turned OFF and the key is not in an ignition position with no power available to the motor of the vehicle, there is a sudden shutting and opening of the sliding door, especially, when the vehicle is on an incline, which may hurt passengers sitting in the vehicle.

Also, existing sliding door mechanisms suffer from a range of issues, particularly, with respect to the gear system that controls movement of the sliding door. The sliding doors are often noisy and prone to vibration which degrades user experience, especially, in vehicles with frequent door operation. Also, the gear ratios commonly used in traditional designs result in jerky, unpredictable movements, causing discomfort and potential damage to the door or vehicle frame. This leads to higher maintenance costs, vehicle downtime, and a lack of reliability, which is particularly problematic in commercial or fleet vehicles where frequent door use is required. Further, a typical sliding door actuator has a drum that occupies a lot of space.

Moreover, hydraulic, pneumatic and electric actuators have been in the market for decades and have evolved over time to reach peak of their efficiency. In the case of window regulators that are operated via manual, pneumatic, hydraulic or electric based mechanisms in vehicles, there is a requirement of an in-built anti pinch functionality to carry out operation of closing or opening of glass door from a current state autonomously on receiving an input signal to safeguard passengers. However, unlike glass movement in the window regulators, typical electrically actuated autonomous sliding doors have a primary and secondary locking latch that operate the sliding door via powered actuators. In the event the actuators are not powered in working condition, the sliding doors have to be operated manually and, therefore, there is a need for back drivability of motors. Further when the vehicle is parked on an inclination, there is a need that the sliding door does not slam shut into closed condition due to gravity but should either stay in its position or move backward or forward with a small creep movement only.

In light of the above-mentioned drawbacks, there is a need for an improved sliding door mechanism that offers enhanced safety, durability, smoother operation, and reduced maintenance. Also, there is a need for an improved sliding door operating device that provides for smooth opening and closing of doors, especially on an inclined road.

Summary of the Invention

In various embodiments of the present invention a back drivable sliding door motor based-operating device (106, 210, 504) is provided. The back drivable sliding door motor based-operating device (106, 210, 504) comprises of a set of gears and pulleys integrable with a motor (208, 514) where the set of gears and pulleys comprises a gear (212) and an integrated gear and rope pulley system (214, 206 and 204). A cable (202) is wound around the integrated gear and rope pulley system (214, 206, 204) with two ends (202a, 202b) of the cable (202) connected to a sliding door (102) of a vehicle (104) forming an infinite drive for actuating the sliding door (102). A maximum tension is supported by the cable (202) based on a coefficient of friction and a pre-tension set in the cable (202) such that the maximum tension supported is more than a total force required to move the sliding door (102), thereby preventing slippage of the cable (202) over the integrated gear and rope pulley system (214, 206, 204).

In various embodiments of the present invention, the gear (212) is a first gear that drives a second gear and pulley (214) of the integrated gear and rope pulley system. The second gear and pulley (214) drives the other two gears and pulleys (third gear and pulley 204 and fourth gear and pulley 206) together. An angle of wrap β is derived based on a weight of the sliding door (102) and pre-determined requirements and is kept high such that contact between surface of the cable (202) and the integrated gear and rope pulley system (214, 206, 204) is high leading to high friction.

In another embodiment of the present invention, the first gear (212) is connected to the shaft (224, 402) of the motor (208, 514) and the integrated gear and rope pulley system (214, 206, 204) is attached to an end cover (216) of the motor (208, 514).

In yet another embodiment of the present invention, the back drivable sliding door motor based-operating device (106, 210, 504) supports a maximum torque which is more than a total torque required to support operation of the sliding door (102). The maximum torque supported is obtained based on the maximum tension supported by the cable (202), pre-tension set on the cable (202) and radius of gear of the integrated gear and rope pulley system (214, 206, 204).

In another embodiment of the present invention, the back drivable sliding door motor based-operating device (106, 210, 504) comprises a multi-turn absolute encoder (220) configured to determine an absolute position of the sliding door (102) when the sliding door (102) is operated manually in the absence of power to the motor (208, 514). In the event the motor (208, 514) starts up and the sliding door (102) is operated by the motor (208, 514), the absolute position where the sliding door (102) was last positioned manually is determined via the multi turn absolute encoder (220) and the motor (208, 514) starts rotating from that determined absolute position.

In various embodiment of the present invention, a restraining mechanism (400) is disposed at a rear end (410) of the back drivable motor based-operating device (106, 210, 504). The restraining mechanism (400) comprises a pair of brake pads (404) which restrains the shaft (224, 402) via friction applied over the shaft (224, 402) of the motor (208, 514), and where the brake pads (404) are positioned 180 degrees apart.

In another embodiment of the present invention, the restraining mechanism (400) comprises restraining pawls (408) including an embedded tensile spring to keep the restraining pawls (408) in a restrained position around a single pivot point. The restraining mechanism (400) comprises a lever (406) that rotates by 90 degrees, upon actuation during motoring, allowing the restraining pawls (408) and brake pads (404) to disengage with the shaft (402) allowing for free motion of the shaft (402), rotor (604), cable (202) and sliding door (102). After motoring is stopped, the lever (406) moves back to its original position and the restraining pawls (408) and brake pads (404) re-engage with the shaft (402) due to the embedded tensile spring present in the restraining pawls (408) such that the shaft (402) and in turn the sliding door (102) does not move or only creeps.

Brief description of the accompanying drawings

The present invention is described by way of embodiments illustrated in the accompanying drawings wherein:

FIG. 1 illustrates a vehicle with a back drivable sliding door motor-based operating device, in accordance with an embodiment of the present invention;

FIG. 2 illustrates the back drivable sliding door motor based-operating device, in accordance with an embodiment of the present invention;

FIG. 2a illustrates a top view and a side view of the back drivable sliding door motor based-operating device, in accordance with an embodiment of the present invention;

FIG. 2b illustrates an angle of wrap of a cable wound around an integrated gear and rope pulley system of the back drivable sliding door motor based-operating device, in accordance with an embodiment of the present invention;

FIG. 3 illustrates variation of tension in the cable wound around the set of integrated gear and rope pulley system, in accordance with an embodiment of the present invention;

FIG. 4, FIG. 4a, FIG. 4b and FIG. 4c illustrate a restraining mechanism of the back drivable sliding door motor based-operating device, in accordance with an embodiment of the present invention;

FIG. 5 illustrates a sensor cover plate of a back end of the back drivable sliding door motor based-operating device, in accordance with an embodiment of the present invention;

FIG. 6 illustrates a sensor cutout in a rotor of the integrated gear-motor system of the back drivable sliding door motor based-operating device, in accordance with an embodiment of the present invention; and

FIG. 7 illustrates a sectional view of the back drivable sliding door motor based-operating device, in accordance with an embodiment of the present invention.

Detailed description of the invention

The disclosure is provided in order to enable a person having ordinary skill in the art to practice the invention. Exemplary embodiments herein are provided only for illustrative purposes and various modifications will be readily apparent to persons skilled in the art. The general principles defined herein may be applied to other embodiments and applications without departing from the scope of the invention. The terminology and phraseology used herein is for the purpose of describing exemplary embodiments and should not be considered limiting. Thus, the present invention is to be accorded the widest scope encompassing numerous alternatives, modifications and equivalents consistent with the principles and features disclosed herein. For purposes of clarity, details relating to technical material that is known in the technical fields related to the invention have been briefly described or omitted so as not to unnecessarily obscure the present invention.

The present invention would now be discussed in context of embodiments as illustrated in the accompanying drawings.

FIG. 1 illustrates a vehicle 104 with a sliding door 102 employing a back drivable sliding door motor based-operating device 106, in accordance with various embodiments of the present invention. The back drivable sliding door motor based-operating device 106 is connected to the sliding door 102 to aid in a smooth sliding operation of the102 and door 102 and may be placed at a specific location based on the design specification of the vehicle 104. FIG. 2 illustrates the back drivable sliding door motor based-operating device 210, in accordance with an embodiment of the present invention. The back drivable sliding door motor based- operating device 210 comprises a set of gears and pulleys integrable with a motor 208. The set of gears and pulleys comprises a gear 212 and an integrated gear and rope pulley system 214, 206 and 204. In an exemplary embodiment of the present invention, the motor 208 is a switched reluctance motor, an induction motor, or a permanent magnet synchronous motor.

The gear 212 is a first gear 212, and the integrated gear and rope pulley system includes a second gear and pulley 214, a third gear and pulley 206 and a fourth gear and pulley 204. The first gear 212 is connected to a shaft 224, 402 (FIG.4) of a rotor 604 (FIG. 6), 716 (FIG. 7) of a motor 208. The back drivable sliding door motor based-operating device 210 comprises a cable 202 wound around the integrated gear and pulley system 214, 206, 204 with two ends 202a, 202b of the cable 202 connected to the sliding door 102 of the vehicle 104 forming an infinite drive for actuating the sliding door 102. In an embodiment of the present invention, the integrated gear and pulley system 214, 206, 204 is attached to an end cover 216 of the motor 208. FIG. 2a illustrates a top view and a side view of the operating device 210. In operation, in an embodiment of the present invention, the first gear 212 integrated with the shaft 224, 402 (FIG.4) of the motor 208 drives the second gear and pulley 214. The second gear and pulley 214 drives the other two gears and pulleys i.e. a fourth gear and pulley 204 and the third gear and pulley 206 together forming a driven geared pulley set.

FIG. 2b illustrates an angle of wrap β of the cable 202 wound around the integrated gear and rope pulley system 214, 206, 204, in accordance with an embodiment of the present invention. In an embodiment of the present invention, the angle of wrap β as illustrated in FIG. 2b is equal to β = <1 + <2 + <3. In this embodiment of the present invention, <1 is not equal to <2 because two ends of the cable 202a, 202b are parallel to each other. In another embodiment of the present invention, <1, <2 and <3 may be equal. In order to prevent any slip between the back drivable sliding door motor based-operating device 210 and the cable 202 connected to the sliding door 102, the angle of wrap β associated with the cable 202 and the integrated gear and rope pulley system 214, 206, 204 is determined and maintained to be high enough to provide adequate traction to the back drivable sliding door motor based-operating device 210. The angle of wrap β associated with the cable 202 and the integrated gear and rope pulley system 214, 206, 204 is maintained high enough to generate necessary difference in tension in the cable 202 at the two ends of the pulley. Particularly in case of high load applications, maintaining high angle of wrap β aids in preventing slippage of the cable 202.

In an exemplary embodiment of the present invention, the sliding door 102 has a mass ( m)= 50 Kg with the vehicle 104 moving at a road inclination of 30% with an angle of inclination θ = 0.29 radians. In this case, maximum gravity force component (Fmax) of the sliding door 102 obtained is: F_max=Sin(θ)*M*g,where g=9.8 m/s^2 i.e. F_max = 140.8 N, as shown in Table 1 below. Similarly, for a vehicle 104 moving over a slope with an inclination of 30%, maximum velocity of the sliding door 102 is 0.225 m/s with an acceleration of 0.5 m/s2. Therefore, in this case, acceleration force component (F_d) of the sliding door 102 is: F_(d )= 28.13 N. Total force (F_totol) required to move the sliding door 102 is F_max+ F_d = 168.93 N , as shown in Table 1 below. Table 1 tabulates the data provided above i.e. the total required force (F_total) to move the sliding door 102 w.r.t road inclination %, mass of the sliding door 102, required acceleration of the sliding door 102 and maximum velocity of sliding door 102. Table 2 above provides the total torque of the motor 208 which is required for operating the sliding door 102 at a particular diameter of the pulley of the integrated gear and rope pulley system 214, 206, 204 in accordance with this exemplary embodiment of the present invention. The gear and pulley diameters of the integrated gear and rope pulley system 214, 206, 204 are the same.
Table 1

Parameter(s) Value Unit
Maximum gravity force component (F_max) of the sliding door 102
Road inclination 30 %
Angle 0.29 Rad
Sin (θ) 0.29 Rad
Mass, m 50 Kg
Gravity (g) 9.8 〖m/s〗^2
Fmax = M*g* Sin (θ) 140.8 N
Acceleration force component (F_d) of the sliding door
Mass, m 50 Kg
Max velocity 0.225 m/s
Acceleration time, t 0.4 S
Acceleration 0.563 〖m/s〗^2
F_d = m*v/t 28.13 N
Total force required to move the sliding door, F total
F_total= F_max + F_d 168.93 N

Table 2
Parameter(s) Value Unit
Diameter of pulley (D) of the integrated gear and rope pulley system 214, 206 and 204 52 Mm
Radius of pulley of integrated gear and rope pulley system 214, 206 and 204, rp = (D/2) 0.026 M
Total torque of the motor 208 required = Total force required * radius of the pulley=F_total* rp 4.4 Nm

In the above example, the angle of wrap β is determined to be high enough and a maximum tension is created on the cable 202 based on one or more parameters including a coefficient of friction and a pre-tension which is set in the cable 202, to prevent slippage of the cable 202. In an embodiment of the present invention, specific high values for angle of wrap β are derived based on weight of the sliding door 102 and pre-defined requirements. A high angle of wrap β results in a large surface contact between surface of the cable 202 and the integrated gear and rope pulley system 214, 206, 204 leading to higher friction. In this case, the parameters include a coefficient of friction (µ) of 0.3 and a pre-tension of 10 N which is set in the cable 202, as shown in Table 3 below.
Table 3

Parameter
Value Unit
Pre-tension set in cable 202 10 N
µ (coefficient of friction) 0.3
β (constant for angle of wrap) 680*π/180=11.87 Radian
C1 (constant) e^μβ= 35.17 Ratio

In the above example, maximum tension supported (T_max) = pre-tension set* C1 i.e.
10.00 *35.17=351.67 N.

As demonstrated above, maximum tension (T_max) created in the cable 202 for the maximum gravity force component (Fmax) of the sliding door 102, as shown in Table 1 above, is equal to 351.6 N. As the maximum tension (T_max) created (351.6 N) is more than total force required (168.93N, as illustrated in Table 1 above) to move the sliding door 102, there is no slip of the cable 202 over the integrated gear and rope pulley system 214, 206, 204.

In this exemplary embodiment of the present invention, gear ratio of the first gear 212, second gear and pulley 214, third gear and pulley 206, and fourth gear and pulley 204 is provided in Table 4 below:
Table 4

Gear and Cable Specification
Parameter Value Unit
First Gear 212
Teeth 22
Gear diameter 9.6 Mm

Second gear and pulley 214, Third gear and pulley 204 and Fourth gear and pulley 206

Teeth 139
Gear diameter (Dia) 56.4 Mm

Pulley diameter (D)
52 Mm
Gear ratio (Teeth of Second/ Third /Fourth gear and pulley 214, 206, 204 divided by teeth of First gear212)
Gear ratio 6.3

Cable 202 Specification
Wire diameter 1.8 Mm
Minimum bending radius 25 Mm
Module of gear representing ratio of pitch diameter to the number of teeth 0.4 mm
Center Distance of a pair of gears representing distance between center shafts of the gears 32.2 mm

Motor 208 Specification
Peak Torque 1 Nm
Maximum motor torque condition constant (M) gear ratio * peak torque of the motor 208 = 6.3*1= 6.3 Nm

Based on a predetermined gear and pulley diameter and gear ratio, as mentioned in Table 4 above, the back drivable sliding door motor based-operating device 106, 210 generates a maximum torque in excess of the required torque of 4.4 Nm (mentioned in Table 1 above) to support operation of the sliding door 102. In this exemplary embodiment of the present invention, considering safety factor, the motor 208 is configured to have a peak torque of around 1 Nm and the gear ratio of the set of gears and pulleys 212, 214, 206, 204 is 6.3. The maximum torque supported by the back drivable sliding door motor based-operating device 106, 210 is 9.64 Nm, which is more than the required torque of 4.4 Nm as expressed by way of the following equation, considering radius of gear of the integrated gear and rope pulley system 214, 206, 204 obtained based on the predetermined gear diameter of the integrated gear and rope pulley system 214, 206, 204 shown in Table 4 above:

Maximum torque supported by the back drivable sliding door motor based-operating device 106, 210 = (T_max (351.67 N) - Pre-tension (10 N)) * radius of gear of the integrated gear and rope pulley system 214, 206, 204 (D/2 = 56.4/2= 0.0282 m) i.e.,
((351.67 N - (10 N)) * 0.0282 m = 9.64 Nm.

Slippage of the cable 202 occurs beyond maximum torque supported by the back drivable motor based operating device 106, 210, which is the desirable condition.

As demonstrated above, in various embodiments of the present invention, the cable 202 is pre-tensioned with respect to the motor 208 and the sliding door 102 to ensure that slippage of the cable 202 does not occur over the integrated gear and rope pulley system 214, 206, 204. The pre-tensioning mechanism generates sufficient friction in the back drivable sliding door motor based-operating device 106, 210 to ensure that torque in excess of 4.4 Nm is supported. The maximum tension of the cable 202 created is based on the angle of wrap, coefficient of friction and magnitude of pre-tensioning added to the cable 202. As illustrated above, the back drivable sliding motor based-operating device 106, 210 is configured to support a maximum torque which is significantly higher than the total torque required to operate the sliding door 102, thereby preventing slippage of the cable 202 over the integrated gear and rope pulley system 214, 206, 204 in accordance with an embodiment of the present invention, as slippage of the cable 202 occurs only after a maximum supported torque is reached.

FIG. 3 illustrates variation of tension in cable 202 wound around the integrated gear and rope pulley system 214, 206, 204, in accordance with an embodiment of the present invention. The applied tension force, T_a= T_t* e^μβ , where T_t is the high side tension force, µ is the coefficient of friction between rope and pulley surface of the rope pulley system part of the set of gears and pulleys, β is angle of wrap, e is the Euler’s constant = 2.718. The values of the applied tension force (T_a) and high side tension force (T_t) are obtained as follows, in accordance with example values of Maximum motor torque condition constant (M) = 6.3 Nm, Constant (C1) = e^μβ = 35.1 and radius of gear of the integrated gear and rope pulley system 214, 206, 204 (rp) = 0.0282 as provided in Tables 3 and 4:

M= (T_a-T_t)*r
T_t = T_a/e^μβ
M = (T_a-T_a/e^μβ )*r
Ta = (C1*M1)/ (C1-1) *r
Ta = 229.94 N
Tt = 6.54

Therefore, the applied tension force is always the larger tension force, and the high side tension force is always the smaller tension force. Advantageously, despite the variation in tension forces in cable 202, there is no slippage of the cable 202 due to the maximum tension (T_max) supported by the cable 202 based on the angle of wrap, coefficient of friction and magnitude of pre-tensioning added to the cable 202, as explained in accordance with various embodiments of the present invention. Conventional chain drive systems are positive drive systems as there is no slip due to the sprockets. Whereas conventional rope drive systems are inherently not positive drive systems due to the possibility of slip. The present invention, in accordance with various embodiments of the present invention, ensures there is no slip and hence makes the rope drive system a positive drive system.

Referring to FIG. 2a, in an embodiment of the present invention a multi-turn absolute encoder 220 is placed in the back drivable sliding door motor based-operating device 210. The multi turn absolute encoder 220 is configured to determine the absolute position of the sliding door 102 (FIG. 1) when the sliding door 102 (FIG. 1) is operated manually in the absence of power to the motor 208. In the event the motor 208 starts up and the sliding door 102 is operated by the motor 208 the absolute position where the sliding door 102 (FIG. 1) was last positioned manually is determined via the multi turn absolute encoder 220 such that the motor 208 starts rotating from the determined absolute position.

In another embodiment of the present invention, a first position sensor 506 (as shown in FIG. 5) in the back drivable sliding door motor based operating device 504 is used to control motor speed, acceleration, etc. to detect position of the rotor 604 (FIG. 6), 716 (FIG. 7) with respect to stator 718 (FIG. 7) of the motor 208 (FIG. 2). Advantageously, the back drivable sliding door motor based operating device 504 eliminates need for a drum that reels and unreels cable 202 (FIG.2) as the sliding door 102 (FIG. 1) opens and closes. The back drivable sliding door motor based operating device 504 allows for an infinite linear drive to be used with the motor 208 (FIG. 2) by replacing conventional concept of angle of wrap in relation to the drum to the improved concept of angle of wrap in relation to the set of gears and pulleys, in accordance with various embodiments of the present invention.

FIG. 4, 4a, 4b, 4c illustrates a restraining mechanism 400 of the back drivable sliding door motor based-operating device 210, 106 (FIG. 2, FIG.1) at one end (rear end 410) of the shaft 224 (FIG.2), 402 of the motor 208 (FIG. 2), in accordance with an embodiment of the present invention. The restraining mechanism 400 is disposed at the rear end 410 of the back drivable sliding door motor based-operating device 210, 106(FIG. 2, FIG.1). The restraining mechanism 400 comprises a pair of brake pads 404 which restrain the shaft 224 (FIG.2), 402 via friction applied over the shaft 224 (FIG.2), 402, where the brake pads 404 are positioned 180 degrees apart. The restraining mechanism 400 also comprises a lever 406 and restraining pawls 408 including an embedded tensile spring that keeps the pawls 408 in a restrained condition around a single pivot point. In operation, during motoring, the actuated lever 406 rotates by 90 degrees allowing the restraining pawls 408 and brake pads 404 to disengage with the shaft 224 (FIG.2), 402 allowing for unrestricted motoring i.e. free motion of the shaft 402, rotor 604 (FIG. 6), 716 (FIG. 7), cable 202 and sliding door 102 (FIG. 1) as illustrated in FIG. 4a in accordance with an embodiment of the present invention.

Once motoring is complete or stopped, the lever 406 moves back to its original position and the restraining pawls 408 and brake pads 404 re-engage with the shaft 224 (FIG.2), 402 due to the embedded tensile spring present in the restraining pawls 408 as illustrated in FIG. 4b in accordance with an embodiment of the present invention, such that the shaft 224 (FIG.2), 402 does not move or only rotates slowly and in turn the sliding door 102 (FIG. 1) does not move or only creeps. In another embodiment of the present invention, instead of restraining pawls 408, the brake pads 404 are fixed in the restrained position with a pair of brake holders 412 disposed on the end cover 216 (FIG. 2) of the motor (FIG. 2), as illustrated in FIG. 4c. In an exemplary embodiment of the present invention, the restraining mechanism 400 is used in case of heavy load applications for example sliding doors used in buses.

FIG. 5 illustrates an outer cover plate 512 of a back end of the back drivable sliding motor based-operating device 504 having the first position sensor 506 and a sensor cover 520. The first position sensor 506 is configured to measure rotation of the rotor 604 (FIG. 6), 716 (FIG. 7) and shaft 224 (FIG. 2), 402 (FIG. 4) of the motor 514. FIG. 6 illustrates a sensor cutout 606 in the rotor 604 (FIG. 6), 716 (FIG. 7) and an area 608 for the first position sensor 506 and the restraining mechanism within a housing envelope of the sensor cover 520. In an embodiment of the present invention, rotor 604 (FIG. 6), 716 (FIG. 7) of the motor 514 is constructed in such a way that the first position sensor 506 may be embedded within an envelope of the motor 514 housing.

FIG. 7 illustrates a sectional view of the back drivable sliding motor based- operating device 106, 210 504 (FIG.1, 2, 5) with cover 704, sensor cover 706, target 708, sensor PCB 710, restraining pawl 712, bush 714, rotor 716, stator 718 and cable 720. In an embodiment of the present invention, bushes are used in the construction of the back drivable sliding door motor based operating device 106, 210, 504 (FIG (s) 1, 2, 5) instead of bearings to limit momentum of the sliding door 102 (FIG. 1) as it is operated. In the event the vehicle 104 (FIG. 1) is parked on an inclined road and the sliding door 102 (FIG. 1) needs to be opened or closed, the sliding door 102 (FIG. 1), advantageously does not slam shut or open abruptly, but only creeps forward or backward due to high rotational inertia generated due to integration of the set of gears and pulleys 212, 214, 206, 204 (FIG. 2) with the motor 208, 514 (FIG(s). 2, 5) and self-restraining feature of the back drivable sliding motor based operating device 106, 210, 504 (FIG (s) 1, 2, 5) when there is no power being delivered to the motor 208, 514 (FIG(s). 2, 5).

In an embodiment of the present invention, the back drivable sliding door motor based operating device 106, 210, 504 (FIG(s) 1, 2, 5) rotates both in clockwise and counterclockwise direction or forward and backward direction as per movement of the sliding door 102 (FIG.1). The back drivable sliding door motor based-operating device 106, 210, 504 (FIG (s) 1, 2, 5) acts as a single compact integrated device to achieve movement of the sliding door 102 (FIG. 1), thereby saving space inside the vehicle 104 (FIG.1). Also, due to high gear ratio between the motor 208, 514 (FIG (s). 2, 5) and sliding door 102 (FIG. 1), the door inertia that is very high is felt a lot less at the motor’s end and the motor 208, 514 (FIG (s). 2, 5) is able to hold up to a particular inclination. Beyond that the motor 208, 514 (FIG(s). 2, 5) does not allow the sliding door 102 (FIG. 1) to slam shut but allows the sliding door 102 (FIG. 1) only to creep slowly.

While the exemplary embodiments of the present invention are described and illustrated herein, it will be appreciated that they are merely illustrative. It will be understood by those skilled in the art that various modifications in form and detail may be made therein without departing from the scope of the invention.

 
Reference Numerals

102: Sliding door
104: Vehicle
106, 210, 504: Back drivable sliding door motor-based operating device
202: Cable
202a, 202b: Ends of the cable connected to the sliding door
204: Fourth gear and pulley
206: Third gear and pulley
208, 514: Motor
212: First gear
214: Second gear and pulley
216: End cover of the motor
220: Absolute encoder
224, 402: Shaft of the motor
400: Restraining mechanism
404: Brake pad
406: Lever
408, 712: Restraining Pawls
410: Rear End
412: Brake holder
506: First position sensor
512: Outer cover plate of the back end of the back drivable motor-based
operating device
520, 706: Sensor cover
604, 716: Rotor
606: Sensor cutout in the rotor
608: Area for the first position sensor and restraining mechanism within a
housing envelope of the end cover 216
704: Cover
708: Target
710: Sensor PCB
714: Bush
718: Stator
720: Cable
, Claims:
1. A back drivable sliding door motor based-operating device (106, 210, 504) comprising of:
a set of gears and pulleys integrable with a motor (208, 514), wherein the set of gears and pulleys comprises a gear (212) and an integrated gear and rope pulley system (214, 206 and 204); and
a cable (202) wound around the integrated gear and rope pulley system (214, 206, 204) with two ends (202a, 202b) of the cable (202) connected to a sliding door (102) of a vehicle (104) forming an infinite drive for actuating the sliding door (102), wherein a maximum tension is supported by the cable (202) based on a coefficient of friction and a pre-tension set in the cable (202) such that the maximum tension supported is more than a total force required to move the sliding door (102), thereby preventing slippage of the cable (202) over the integrated gear and rope pulley system (214, 206, 204).

2. The back drivable sliding motor based-operating device (106, 210, 504) as claimed in claim 1, wherein the gear (212) is a first gear that drives a second gear and pulley (214) of the integrated gear and rope pulley system and the second gear and pulley (214) drives the other two gears and pulleys (third gear and pulley 204 and fourth gear and pulley 206) together , and wherein an angle of wrap β is derived based on a weight of the sliding door (102) and pre-determined requirements and is kept high such that contact between surface of the cable (202) and the integrated gear and rope pulley system (214, 206, 204) is high leading to high friction.

3. The back drivable sliding door motor based-operating device (106, 210, 504) as claimed in claim 2, wherein the first gear (212) is connected to the shaft (224, 402) of the motor (208, 514) and the integrated gear and rope pulley system (214, 206, 204) is attached to an end cover (216) of the motor (208, 514).

4. The back drivable sliding door motor based-operating device (106, 210, 504) as claimed in claim 2, wherein the back drivable sliding door motor based-operating device device (106, 210, 504) supports a maximum torque which is more than a total torque required to support operation of the sliding door (102), wherein the maximum torque supported is obtained based on the maximum tension supported by the cable (202), pre-tension set on the cable (202) and radius of gear of the integrated gear and rope pulley system (214, 206, 204).

5. The back drivable sliding door motor based-operating device (106, 210, 504) as claimed in claim 1, wherein the back drivable sliding door motor based-operating device device (106, 210, 504) comprises a multi-turn absolute encoder (220) configured to determine an absolute position of the sliding door (102) when the sliding door (102) is operated manually in the absence of power to the motor (208, 514) such that in the event the motor (208, 514) starts up and the sliding door (102) is operated by the motor (208, 514), the absolute position where the sliding door (102) was last positioned manually is determined via the multi turn absolute encoder (220) and the motor (208, 514) starts rotating from that determined absolute position.

6. The back drivable motor based-operating device (106, 210, 504) as claimed in claim 1, wherein a restraining mechanism (400) is disposed at a rear end (410) of the back drivable motor based-operating device (106, 210, 504), and wherein the restraining mechanism (400) comprises a pair of brake pads (404) which restrains the shaft (224, 402) via friction applied over the shaft (224, 402) of the motor (208, 514), and wherein the brake pads (404) are positioned 180 degrees apart.

7. The back drivable motor based-operating device (106, 210, 504) as claimed in claim 6, wherein the restraining mechanism (400) comprises:
restraining pawls (408) including an embedded tensile spring to keep the restraining pawls (408) in a restrained position around a single pivot point; and
a lever (406) that rotates by 90 degrees, upon actuation during motoring, allowing the restraining pawls (408) and brake pads (404) to disengage with the shaft (402) allowing for free motion of the shaft (402), rotor (604), cable (202) and sliding door (102), wherein after motoring is stopped, the lever (406) moves back to its original position and the restraining pawls (408) and brake pads (404) re-engage with the shaft (402) due to the embedded tensile spring present in the restraining pawls (408) such that the shaft (402) and in turn the sliding door (102) does not move or only creeps.