Patent Description:
In general, a forklift is a kind of special vehicles used to lift or transport cargo in various industrial sites. Such a forklift basically includes a fork or a carriage for lifting or unloading cargo outside the vehicle, and an engine or a motor mounted inside a forklift body to drive the forklift.

Moreover, an industrial vehicle such as a forklift includes a power transmission system that motors using electricity or hydraulic pressure and respectively mounted on driving wheels are merged with brake units and planetary gear assemblies so as to simplify driving and control systems. However, since the motors, the driving means and the braking means are directly connected to each other, the industrial vehicle has a disadvantage in that the vehicle shakes or a driving direction is changed due to an operation time difference and an operation pressure difference of the brake units respectively mounted on the driving wheels.

Furthermore, since a motor driving gear directly connected to the rotary shaft of the driving motor is arranged to be biased toward one side of the vehicle and a differential unit geared with the motor driving gear is also arranged at the same position, a distance between right and left wheel adapters which transfer driving power from the differential unit to wheels mounted outside is varied, and lengths of driving shafts which transfer driving power distributed from the differential unit to the wheel adapters are different from each other. So, there is a problem in that the driving shafts and the wheel adapters must be manufactured differently. <CIT> discloses a single axle drive brake according to the preamble of claim <NUM>.

Accordingly, the present invention has been made in view of the above-mentioned problems occurring in the related art, and it is an object of the present invention to provide a single drive axle brake for an electric forklift, which includes: a differential unit for separating and transferring driving power transmitted from a motor to both sides by driving power of one motor; a differential gear unit formed in the differential unit for distributing and transferring the driving power transmitted from the motor to wheels disposed at both sides; and a brake unit for restricting the differential gear unit so that just one brake unit can restrict a power transmission unit for transferring the driving power generated from the motor to the differential gear unit and a power shaft for transferring driving power provided from the differential gear unit to the wheels, thereby narrowing an interval between the wheels disposed at both sides of the differential unit, and enhancing safety of the forklift by providing the center of the drive axle lower than that of the conventional art.

It is another object of the present invention to provide a single drive axle brake for an electric forklift in which the brake unit is mounted on the opposite side of a motor gear since the differential unit geared with a motor driving gear is biased to one side and the center of gravity of the forklift is changed, thereby reducing a deviation in the center of gravity of a power unit.

It is a further object of the present invention to provide a single drive axle brake for an electric forklift in which a power transmission module is mounted to be biased to any one among both side wheel adapters, the brake unit is attached to the side of the differential unit which is longer so as to separate power shafts since driving shafts for transferring the driving power to the wheel adapters are different in length, and the power shaft and the driving shaft are connected by a spline collar supported by a bearing, thereby making lengths and sizes of the driving shafts equal so as to be used in common.

The technical problems to be achieved through the present invention are not limited as mentioned above, and other technical problems not mentioned herein will be obviously understood by one of ordinary skill in the art through the following description.

To accomplish the above-mentioned objects, according to the present invention, there is provided a single drive axle brake according to claim <NUM>.

In addition, the main brake hub has a cylindrical shape that cylinders having different diameters are joined to each other to form a stepped portion, wherein the inner circumferential surface of a cylindrical part having a relatively smaller diameter is joined to the outer circumferential surface of the differential gear case and the outer circumferential surface of the cylindrical part having a relatively larger diameter is joined to the main disc.

Moreover, the subsidiary brake includes a subsidiary brake hub and a subsidiary disc coupled to the subsidiary brake hub. The inner circumferential surface of the subsidiary brake hub is coupled to the outer circumferential surface of the power shaft, and the subsidiary disc is coupled to the outer circumferential surface of the subsidiary brake hub at regular intervals.

Furthermore, the subsidiary brake hub has a first cylinder having a smaller diameter and a second cylinder having a larger diameter which are connected with each other by a connection member, the inner circumferential surface of the first cylinder is joined to the outer circumferential surface of the power shaft, and the subsidiary disc is joined to the outer circumferential surface of the second cylinder. Plates have a doughnut-shape of which the center is perforated, two or more assembly holes into which support rods coupled to the outer case are inserted are formed at a predetermined position of the doughnut-shaped disc plate. The inner diameter of the assembly hole is formed to be larger than the outer diameter of the support rod.

Additionally, the main disc and the subsidiary disc face each other and are arranged adjacent to each other. The fixed plates are inserted between the main discs and between the subsidiary discs, and the fixed plate is also inserted between the main disc and the subsidiary disc facing each other.

In addition, the main disc and the subsidiary disc have a doughnut shape of which the center is perforated. The inner diameter of the center of the main disc and the inner diameter of the center of the subsidiary disc are equal, and the outer diameter of the main disc and the outer diameter of the subsidiary disc are also equal. Since each plate is disposed between the main disc and the subsidiary disc, the discs and the plates are sequentially arranged, and the plates are arranged at both ends, the plates, the main discs, and the subsidiary discs are compressed and stopped by a hydraulic cylinder which presses the plates, and the main brake hub and the subsidiary brake hub are stopped when the main disc and the subsidiary disc are stopped.

The disc of one among the plates of both ends is pressed by the hydraulic cylinder, and a plate supporter for supporting the other plate approaches the other plate to compress the plate, the main disc and the subsidiary disc by compression of the hydraulic cylinder. Therefore, the plates, the main discs and the subsidiary discs can be supported and compressed by the plate supporter.

Furthermore, the hydraulic cylinder is arranged on the opposite side of the differential unit to operate only one cylinder so that the main disc and the subsidiary disc are stopped simultaneously.

The inside of the outer case is machined into a multi-stage cylinder. A piston mounting portion on which a piston of the hydraulic cylinder is mounted to move, a plate mounting portion on which the plates, the main discs and the subsidiary disc are mounted, and a plate support mounting portion to which a plate supporter is coupled and fixed are formed on the outer case in consecutive order.

The piston is mounted on the piston mounting portion. The piston advances toward the plate mounting portion by a fluid supplied from the outside, and a piston return unit for moving the advanced piston to an initial position is provided.

In addition, the central line of the driving shaft of the differential unit is referred to as a first center line, and a line crossing the first center line at the center of the differential unit is referred to as a second center line. The left side from the second center line is called one side and the right side from the second center line is called the other side. A reduction means for reducing driving power of the motor and transferring the driving power to the differential unit, and a power transmission housing formed to surround the reduction means and a differential gear unit are provided, and the brake unit is coupled to the other side of the power transmission housing.

The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings.

According to the present invention, the single drive axle brake for an electric forklift includes: a differential unit for separating and transferring driving power transmitted from a motor to both sides by driving power of one motor; a differential gear unit formed in the differential unit for distributing and transferring the driving power transmitted from the motor to wheels disposed at both sides; and a brake unit for restricting the differential gear unit so that just one brake unit can restrict a power transmission unit for transferring the driving power generated from the motor to the differential gear unit and a power shaft for transferring driving power provided from the differential gear unit to the wheels, thereby narrowing an interval between the wheels disposed at both sides of the differential unit, and enhancing safety of the forklift by providing the center of the drive axle lower than that of the conventional art.

Furthermore, the single drive axle brake for an electric forklift according to the present invention can reduce a deviation in the center of gravity of a power unit since the brake unit is mounted on the opposite side of a motor gear since the differential unit geared with a motor driving gear is biased to one side and the center of gravity of the forklift is changed.

In addition, the single drive axle brake for an electric forklift according to the present invention has a structure that a power transmission module is mounted to be biased to any one among both side wheel adapters, the brake unit is attached to the side of the differential unit which is longer so as to separate power shafts since driving shafts for transferring the driving power to the wheel adapters are different in length, and the power shaft and the driving shaft are connected by a spline collar supported by a bearing, thereby making lengths and sizes of the driving shafts equal so as to be used in common.

Hereinafter, preferred embodiments will be described with reference to the accompanying drawings. In the drawings, thicknesses of lines and sizes of constituent elements may be exaggerated for clarity and convenience in explanation.

Furthermore, terms to be described later are defined in consideration of the functions of the present invention, and may differ depending on the intentions of a user or an operator or custom. Accordingly, such wordings should be defined on the basis of the contents of the overall specification.

<FIG> is a schematic diagram of a single drive axle according to a conventional art, <FIG> is a cross-sectional view illustrating a brake structure of an electric forklift according to a conventional art, <FIG> is a cross-sectional view illustrating a single drive axle according to a preferred embodiment of the present invention, <FIG> is an enlarged view of a part "B" of <FIG>, <FIG> is a cross-sectional view illustrating a brake structure according to the present invention, and <FIG> is a cross-sectional view illustrating an outer case of a brake unit according to the present invention.

In order to better understand the development environment of a single drive axle of an electric forklift using an electric motor according to an embodiment of the present invention, <FIG> illustrates a single drive axle according to a conventional art.

Referring to <FIG>, The single drive axle according to the conventional art includes: a motor brake <NUM> mounted to brake a motor shaft connected to a motor; a differential unit <NUM> connected to the motor shaft via gears to receive driving power of the motor to transfer the driving power to wheels and divided into right and left driving shafts; right and left driving units into which driving shafts for transferring the driving power from the differential unit to the wheels are inserted; and driving shaft brakes <NUM> and <NUM> to apply braking power of the driving shafts.

In addition, <FIG> is a cross-sectional view illustrating a brake structure attached to a front wheel of the electric forklift according to the conventional art.

As illustrated in <FIG>, components for transferring a rotational force of the motor to the wheels mounted outside are included inside two housings.

As described above, since the differential unit and the driving system for transferring the driving force to the wheels are all disposed inside the two housing, there is difficulty in machining and handling the housings.

Moreover, since brake systems are respectively attached to the right and left driving shafts on which the wheels are mounted, the forklift vehicle shakes or a driving direction is changed due to an operation time difference and an operation binding force of the brake units respectively mounted on the driving wheels.

Furthermore, as illustrated in <FIG>, the motor driving gear directly connected to the rotary shaft of the driving motor is arranged to be biased to one side of the forklift vehicle. Accordingly, since a distance between the right and left wheel adapters transferring the driving force from the differential unit to the wheels mounted outside is varied and lengths of the driving shafts transferring the driving force from the differential unit to the wheel adapters are different, they must be manufactured individually.

Additionally, since the differential unit geared with the motor driving gear is biased to one side, the center of gravity of the forklift vehicle is also biased to one side.

In the single drive axle according to the conventional art, the brake unit is mounted on both side wheel adapters. However, in order to solve the problem of the conventional art and solve the technical problem mentioned above, in a single drive axle of an electric forklift using an electric motor according to the present invention, a brake unit for restricting a differential gear of a differential unit geared with a motor driving gear is located to be opposed to a motor driving gear so as to reduce a deviation in the center of gravity of a forklift vehicle.

In addition, the brake unit for restricting the differential gear is formed to restrict a differential gear case which is combined with a crown gear of the differential gear.

Moreover, when the brake unit restricts the differential gear case, all of power transmission units transferring driving power of a motor to the differential unit are restricted and stopped.

Moreover, the wheels are stopped generally, but if any one of the wheels slips, there is a difference in friction force between the wheels due to the slip. Accordingly, there is a difference also in rotational force applied to differential side gears respectively connected to the driving shafts transferring the driving power from the differential gear to the wheels mounted outside. Due to the difference in rotational force applied to the two differential side gears, differential pinion gears respectively geared with the differential side gears run idle. So, there is a difference in rotational angle of the two wheels due to idling of the differential pinion gears, and it may cause a vibration of the forklift vehicle or a change in driving direction. The single drive axle of the electric forklift using the electric motor according to the present invention further includes a subsidiary brake for restricting and stopping rotation of the driving shaft transferring the driving power from the differential gear. Therefore, a main brake, which stops the rotation of the differential gear case, and the subsidiary brake are restricted simultaneously so as to stop the rotation.

As described above, the single drive axle according to the conventional art has the brake units disposed inside the right and left wheel adapter modules, but the single drive axle according to the present invention has the brake unit disposed on the differential gear. Therefore, the single drive axle according to the present invention can narrow the distance between the wheels disposed at the right and left sides of the driving shafts, make the center of the drive axle lower than the conventional art, and reduce the deviation of the center of gravity so as to reduce noise of the forklift and improve safety.

Furthermore, the motor driving gear, a reduction means, and the differential unit which separates and transfers driving power transferred from the reduction means are manufactured into one module, namely, a power transmission module. The components transferring the driving power transferred from the power transmission module to the wheels mounted outside are modularized to be detachable, thereby providing convenience in maintenance and manufacturing.

Especially, since the power transmission module is mounted to be biased to one wheel adapter among both wheel adapters and the driving shafts transferring driving power to the wheel adapters are different in length, the brake unit is attached to the side of the differential unit which is longer so as to separate the driving shafts, and a power shaft and the driving shaft are connected by a spline collar supported by a bearing, thereby making the length and size of both driving shafts equal.

Gear cutting is applied to the inside of a reduction unit housings of the both wheel adapters so that the reduction unit serves as a ring gear, thereby integrating the reduction unit housing and the ring gear into a single module. Therefore, the single drive axle for the electric forklift according to the present invention can improve convenience in repairing and manufacturing.

Hereinafter, referring to the drawings, a preferred embodiment of the present invention will be described in detail.

As illustrated in <FIG>, in order to transfer driving power of the motor to the wheels disposed at the right and left sides of the driving shaft, the single drive axle for the electric forklift according to the present invention includes: a reduction means <NUM> decelerating driving power of a motor <NUM> to transfer the driving power to a differential unit <NUM>; the differential unit <NUM> disposed in parallel with the shaft of the motor <NUM> to separate and transfer the driving power transferred from the reduction means <NUM> to both sides; and right and left wheel adapter modules <NUM> and <NUM> respectively combined with both sides of the differential unit <NUM> to transfer the driving power from the differential unit <NUM> to the wheels mounted outside.

Now, a brake unit <NUM> for restricting a differential gear unit <NUM> will be described. The differential gear unit <NUM> includes: a crown wheel <NUM> of the differential unit receiving the driving power from the motor; a differential gear case <NUM> coupled with the crown wheel <NUM>; a differential pinion gear mounted to be able to rotate and revolve with the differential gear case <NUM>; and differential side gears <NUM> and <NUM> geared with the differential pinion gear inside the differential gear case <NUM> coupled with the crown wheel <NUM> of the differential unit. The brake unit <NUM> is formed to restrict the differential gear case <NUM>.

Additionally, a power shaft <NUM> for transferring the driving power provided from the differential gear unit <NUM> is connected to the differential side gears <NUM> and <NUM> of the differential gear. The brake unit <NUM> further includes: a main brake <NUM> for stopping the rotation of the differential gear case <NUM>; and a subsidiary brake <NUM> for stopping the rotation of the power shaft <NUM>.

The main brake <NUM> includes a main brake hub <NUM> and main discs <NUM> combined with the main brake hub. A portion of the inner circumferential surface of the main brake hub is joined to the outer circumferential surface <NUM> of the differential gear case, and the main discs <NUM> are combined on the outer circumferential surface <NUM> of the main brake hub at regular intervals.

In addition, the main brake hub <NUM> has a cylindrical shape that cylinders having different diameters are joined to each other to form a stepped portion, wherein the inner circumferential surface of a cylindrical part having a relatively smaller diameter is joined to the outer circumferential surface <NUM> of the differential gear case and the outer circumferential surface of the cylindrical part having a relatively larger diameter is joined to the main disc <NUM>.

The subsidiary brake <NUM> includes a subsidiary brake hub <NUM> and a subsidiary disc <NUM> coupled to the subsidiary brake hub, wherein the inner circumferential surface of the subsidiary brake hub is coupled to the outer circumferential surface of the power shaft, and the subsidiary disc <NUM> is coupled to the outer circumferential surface <NUM> of the subsidiary brake hub at regular intervals.

In addition, the subsidiary brake hub <NUM> has a first cylinder having a smaller diameter and a second cylinder having a larger diameter which are connected with each other by a connection member, the inner circumferential surface of the first cylinder is joined to the outer circumferential surface of the power shaft, and the subsidiary disc <NUM> is joined to the outer circumferential surface of the second cylinder.

Additionally, fixed plates <NUM> are inserted between the joined main discs <NUM> and between the subsidiary discs <NUM> at regular intervals. Each of the plates <NUM> is a doughnut-shaped disc plate of which the center is perforated. Two or more assembly holes <NUM> into which support rods coupled to the outer case <NUM> are inserted are formed toward an outer diameter portion of the doughnut-shaped disc plate. The inner diameter of the assembly hole <NUM> is formed to be larger than the outer diameter of the support rod. Therefore, the plate <NUM> is movable according to a guide of the support rod when being fixed.

Furthermore, the main disc <NUM> and the subsidiary disc <NUM> face each other and are arranged adjacent to each other. The fixed plates <NUM> are inserted between the main discs <NUM> and between the subsidiary discs <NUM>. The fixed plate <NUM> is also inserted between the main disc <NUM> and the subsidiary disc <NUM> facing each other. The main disc <NUM> and the subsidiary disc <NUM> have a doughnut shape of which the center is perforated. The inner diameter of the center of the main disc and the inner diameter of the center of the subsidiary disc are equal, and the outer diameter of the main disc and the outer diameter of the subsidiary disc are also equal.

Additionally, as each plate <NUM> is disposed between the main disc <NUM> and the subsidiary disc <NUM>, the discs and the plates are sequentially arranged. The plates <NUM> are disposed at both ends thereof, and the plates and the discs are compressed by a hydraulic cylinder <NUM> pressing the plates <NUM> so that the main disc <NUM> and the subsidiary disc <NUM> are stopped. When the main disc <NUM> and the subsidiary disc <NUM> are stopped, the main brake hub <NUM> and the subsidiary brake hub <NUM> are stopped.

In addition, the hydraulic cylinder <NUM> is arranged on the opposite side of the differential unit so that the main disc <NUM> and the subsidiary disc <NUM> are stopped simultaneously by one cylinder.

In the single drive axle of the electric forklift, the central line of the driving shaft of the differential unit <NUM> is referred to as a first center line, and a line crossing the first center line at the center of the differential unit is referred to as a second center line. The left side from the second center line is called one side and the right side from the second center line is called the other side.

The single drive axle of the electric forklift includes: a motor driving gear <NUM> directly connected to the rotary shaft <NUM> of the motor; a reduction gear rotary shaft <NUM> which is parallel with the rotary shaft <NUM> of the motor; a first reduction gear <NUM> of the reduction means <NUM> gearing with the motor driving gear <NUM>; and a second reduction gear <NUM> coupled to the same shaft as the first reduction gear.

The single drive axle further includes a differential gear <NUM> formed to be geared with the second reduction gear <NUM>.

Moreover, the single drive axle further includes a power transmission housing <NUM> formed to surround the motor driving gear <NUM>, the reduction means <NUM> and the differential gear <NUM>, and the power transmission housing <NUM> is formed to be divided into one side power transmission housing <NUM> and the other side power transmission housing <NUM>.

Furthermore, the differential gear unit <NUM> includes: a crown wheel <NUM> of the differential unit geared with the second reduction gear <NUM> of the reduction means <NUM>; and small differential gears <NUM> and <NUM> and one side and the other side large differential gears <NUM> and <NUM> which separate and transfer the driving power of the crown wheel <NUM> to both sides. Therefore, the rotational force of the motor is separated and transferred to the both driving shafts through the one side and the other side large differential gears <NUM> and <NUM> of the differential gear unit <NUM> after passing through the reduction means <NUM>.

Additionally, the one side driving shaft <NUM> coupled to the one side large differential gear <NUM> is connected to one side wheel adapter module <NUM>, and the other side driving shaft <NUM> is connected to the other side large differential gear driving shaft and the other side large differential gear power shaft <NUM> connected to the brake unit <NUM>. The other side driving shaft <NUM> is formed to be connected to the other side wheel adapter module <NUM>.

Now, the configuration that the driving power from the power transmission housing <NUM> is transferred to one side wheel adapter <NUM> mounted outside will be described.

The left wheel adapter module <NUM> includes: one side wheel adapter <NUM> that the wheel is mounted outside; and one side reduction unit <NUM> which reduces the driving power transferred from the one side driving shaft <NUM> and transfers the driving power to the one side wheel adapter <NUM>.

The one side reduction unit <NUM> is a planet gear reduction unit including: a sun gear coupled to the driving shaft; a plurality of planet gears mounted to engage with the sun gear to rotate; and a ring gear surrounding the planet gear. Gear cutting is applied to the inside of the one side reduction unit housing <NUM> so that the reduction unit serves as a ring gear, thereby integrating the housing and the ring gear into a single module.

In addition, one side wheel adapter connection bridge <NUM> is disposed between the one side reduction unit housing <NUM> and the one side power transmission housing <NUM>. On one side <NUM> of the one side wheel adapter connection bridge <NUM>, formed are a first coupling part <NUM> coupled with the other side of the one side reduction unit housing <NUM>, and a second coupling part <NUM> formed on the outer diameter portion adjacent to the other side <NUM> of the one side wheel adapter connection bridge <NUM> and coupled with the one side power transmission housing <NUM> in which the reduction means <NUM> and the differential gear unit <NUM> are embedded.

Moreover, the one side wheel adapter <NUM> includes an adapter housing <NUM> surrounding the one side wheel adapter <NUM>, and one side of the one side reduction unit housing <NUM> is coupled to the other side of the adapter housing <NUM>. An edge portion of a predetermined width is disposed on the coupled portion between the adapter housing <NUM> and the one side wheel adapter connection bridge <NUM>.

Furthermore, the edge portion of the one side reduction unit housing <NUM> has a through hole formed at a predetermined portion, and a bolt is inserted into the through hole of the one side wheel adapter <NUM> so that the one side wheel adapter and the one side wheel adapter connection bridge are coupled by bolt fastening at the edge portion of the one side wheel adapter connection bridge <NUM>.

Additionally, the outer diameter of the edge portion having a predetermined width and the outer diameter of the reduction unit housing <NUM> are equal at the coupled portion between the adapter housing <NUM> and the one side wheel adapter connection bridge <NUM>.

Through the above configuration, the left wheel adapter module <NUM> has the wheel adapter <NUM> and the reduction unit <NUM> which can be assembled and disassembled on the wheel adapter connection bridge <NUM> using a plurality of fastening bolts. The reduction unit <NUM> has a plurality of planet gears embedded therein, and the ring gears surrounding the planet gears is integrated with the housing <NUM> to be modularized. Therefore, a process of machining a ring gear assembly unit for accommodating the ring gear inside the housing and a process of accommodating and fixing the ring gear inside the ring gear assembly unit may be omitted.

In addition, the left wheel adapter module <NUM> has high reduction ratio since the reduction unit <NUM> having the planet gears is mounted on the left wheel adapter module <NUM>.

Moreover, when the planet gear gets damaged, the integrated reduction unit module can be replaced to be repaired conveniently and rapidly.

Furthermore, an outer diameter portion <NUM> formed near the other side surface <NUM> of the one side wheel adapter connection bridge <NUM> has a stepped portion <NUM> formed at a position spaced apart from the other side surface <NUM> at a predetermined distance. An assembly hole <NUM> into which the outer diameter portion is inserted is formed in the one side power transmission housing <NUM>, and the outer diameter portion <NUM> having the stepped portion <NUM> of the one side wheel adapter connection bridge <NUM> is forcedly fitted and coupled into the assembly hole <NUM>.

In addition, a bearing insertion inner diameter portion <NUM> into which a bearing <NUM> supporting the rotary shaft of the crown wheel <NUM> of the differential unit is inserted is disposed inside the outer diameter portion <NUM> of the one side wheel adapter connection bridge <NUM>. The assembly hole <NUM> has a predetermined width in the direction of the first center line, and has a mounting portion <NUM> formed therein to be at right angles to the assembly hole <NUM>.

Additionally, the mounting portion <NUM> includes a coupling ring <NUM> for coupling the one side wheel adapter connection bridge <NUM> and the one side power transmission housing <NUM>, and a portion of the coupling ring <NUM> is provided with an overlapping portion formed to overlap the other side surface <NUM> of the one side wheel adapter connection bridge. A screw hole is formed in the other side <NUM> of the connection bridge, and a through-hole is formed in the overlapping portion of the coupling ring <NUM> so that the connection bridge and the coupling ring are screw-coupled through the through-hole.

In other words, the bearing insertion inner diameter portion <NUM> is provided inside the outer diameter portion <NUM> in which the stepped portion <NUM> of the one side wheel adapter connection bridge <NUM> is formed.

The one side power transmission housing <NUM> has the assembly hole <NUM>, and the assembly hole <NUM> has a predetermined width in the direction of the first center line and the mounting portion <NUM> which is at right angles to the assembly hole <NUM> is disposed inside the assembly hole.

After the outer diameter portion <NUM> having the stepped portion <NUM> of the one side wheel adapter connection bridge <NUM> is forcedly fit into the assembly hole <NUM> formed in the one side power transmission housing <NUM>, the bearing <NUM> which supports the rotary shaft of the crown wheel <NUM> of the differential unit is inserted into the bearing insertion inner diameter portion <NUM> formed in the outer diameter portion <NUM>.

The coupling ring <NUM> is provided at the mounting portion <NUM> of the one side power transmission housing <NUM> on which the outer diameter portion <NUM> having the stepped portion <NUM> is fitted, and is coupled to the one wheel adapter connection bridge <NUM> by means of a fastening bolt through the through-hole formed in the coupling ring <NUM>.

The assembly hole <NUM> formed in the one side power transmission housing <NUM> is forcedly fitted and coupled with the outer diameter portion <NUM> having the stepped portion <NUM>, and the coupling ring <NUM> is fastened to the one side wheel adapter connection bridge <NUM> by means of a fastening bolt, thereby pressurizing and fixing the mounting portion <NUM> of the one side power transmission housing <NUM>.

In addition, in order to set an assembly position of the forcedly fit components, position setting protrusions and position setting groove portions, or position indication portions may be added on the outer diameter portion <NUM> having the stepped portion <NUM> and the assembly hole <NUM> formed in the one side power transmission housing <NUM>.

Referring to <FIG> and <FIG>, the present invention will be described.

The other side power transmission housing <NUM> is coupled to the other side of the one side power transmission housing <NUM>.

The single drive axle brake for an electric forklift according to the present invention includes: the motor driving gear <NUM> directly connected to the shaft of the motor <NUM> inside the one side power transmission housing <NUM> and the other side power transmission housing <NUM>; the reduction gear rotary shaft <NUM> disposed parallel with the rotary shaft <NUM> of the motor; a first reduction gear <NUM> of the reduction means <NUM> geared with the motor driving gear <NUM>; and the differential gear unit <NUM> including the crown wheel <NUM> of the differential unit formed to be geared with the second reduction gear <NUM>, the small differential gears <NUM> and <NUM> separating and transferring driving power of the crown wheel <NUM> to both sides, and one side and the other side large differential gears <NUM> and <NUM>.

As described above, the differential unit disposed parallel with the shaft of the motor can transfer driving power of the motor to the right and left wheels, the reduction means arranged between the motor shaft and the differential unit which are arranged parallel to reduce the speed of the motor can easily adjust speed to reduce noise, and the drive axle which gets lower in the center of the drive axle can improve safety of the forklift.

Moreover, the brake unit <NUM> is coupled to the other side of the other side power transmission housing <NUM>. The brake unit <NUM> has the main brake <NUM> for restricting the differential gear case <NUM> coupled to the other side large differential gear <NUM> and the subsidiary brake <NUM> for restricting the power shaft <NUM>, and an outer case <NUM> of the brake unit is disposed to protect the brake unit from an external risk.

The shape of the outer case <NUM> will be described.

The inside of the outer case <NUM> is machined into a multi-stage cylinder. A piston mounting portion <NUM> on which a piston of the hydraulic cylinder <NUM> is mounted to move, a plate mounting portion <NUM> on which the plates, the main discs <NUM> and the subsidiary disc <NUM> are mounted, and a plate support mounting portion <NUM> to which a plate supporter <NUM> is coupled and fixed are formed on the outer case <NUM> in consecutive order.

The piston <NUM> is mounted on the piston mounting portion <NUM>. The piston <NUM> advances toward the plate mounting portion <NUM> by a fluid supplied from the outside, and a piston return unit <NUM> for moving the advanced piston <NUM> to an initial position is provided.

The subsidiary disc <NUM> and the main disc <NUM> are sequentially arranged on the plate mounting portion <NUM>, and the plate <NUM> is arranged between the subsidiary disc <NUM> and the main disc <NUM>.

The plate supporter <NUM> is mounted on the plate support mounting portion <NUM>.

A rotary bearing for supporting the differential gear case <NUM> is provided on an inner diameter portion of one side surface of the plate supporter <NUM>, and a support portion <NUM> for supporting the plate supporter <NUM> is provided on the other side surface. A coupling hole <NUM> into which the support rod is inserted so as to fix the plate <NUM> to the outer case <NUM> is formed on a flange <NUM> formed toward the outer diameter at a predetermined distance from the other side.

In addition, the support rod having a spiral portion formed at an end portion thereof passes through the coupling hole <NUM> of the flange <NUM> and the assembly holes <NUM> formed in the plurality of plates and is coupled with the spiral portion of the outer case <NUM>, so that the plurality of plates <NUM> are fixed to the outer case <NUM>.

That is, when the fluid generated from the outside presses the plates <NUM> by the piston <NUM> of the hydraulic cylinder <NUM>, the subsidiary disc <NUM> and the main discs <NUM> which are arranged sequentially compress and stop the plates <NUM> fixed to the outer case <NUM> by the support rod arranged between the subsidiary disc <NUM> and the main discs <NUM>. When the main discs <NUM> and the subsidiary disc <NUM> are stopped, the main brake hub <NUM> and the subsidiary brake hub <NUM> are also stopped.

Furthermore, as the main brake hub <NUM> and the sub brake hub <NUM> are stopped, rotation of the differential gear case <NUM> and the power shaft <NUM> is stopped.

In addition, with reference to <FIG>, the present invention will be described.

The other side of the housing <NUM> of the differential brake unit <NUM> is coupled to the other side wheel adapter module <NUM>. The other side wheel adapter module <NUM> includes: the other side wheel adapter <NUM> where the wheel is mounted on the outside; the other side reduction unit <NUM> which decelerates the driving power transferred from the other side driving shaft <NUM> and transfers the decelerated power to the other side wheel adapter <NUM>; and the other side wheel adapter connection bridge <NUM> which is formed to connect the other side reduction unit <NUM> and the differential unit brake unit <NUM>.

In addition, a coupling portion <NUM> is formed near one side surface <NUM> of the other side wheel adapter connection bridge <NUM>, and a coupling flange <NUM> protruding from the one side surface <NUM> toward the outer diameter at a predetermined interval is disposed on the coupling portion <NUM>. The coupling flange <NUM> has a through-hole. An assembly hole <NUM> into which the coupling portion <NUM> is inserted is formed on the other side of the housing <NUM> of the differential brake unit <NUM>, and a spiral hole <NUM> is formed at the other side near the assembly hole <NUM>.

Moreover, a coupling portion <NUM> having a coupling flange <NUM> of the other side wheel adapter connection bridge <NUM> is forcedly fitted into the assembly hole <NUM>. A coupling bolt is coupled to a spiral hole <NUM> formed in the other side near the assembly hole <NUM> of the other side power transmission housing <NUM> through a through-hole formed in the coupling flange <NUM>.

As described above, the power transmission module provided in the power transmission housing having the motor is installed between the left and right wheel adapters to be biased toward any one wheel adapter, and so, the length of the other side driving shaft for transferring driving power to the right wheel adapter is longer than the one side driving shaft for transferring driving power to the left wheel adapter.

As described above, since the one side driving shaft and the other side driving shaft are different in length, there is a problem in that the both side driving shafts are individually manufactured and stored, and it is necessary to use them commonly.

In order to solve the above problem, a bearing insertion inner diameter portion <NUM> into which a bearing capable of connecting and supporting the power shaft <NUM> of the differential unit is disposed inside the coupling portion <NUM> formed on the one side surface <NUM> of the other side wheel adapter connection bridge <NUM>. A spline collar <NUM> supported by the bearing is mounted in the bearing insertion inner diameter portion <NUM>.

The spline collar supported by the bearing is mounted at a position corresponding to the different lengths of the both driving shafts. The other side driving shaft which is longer than the one side driving shaft is divided into the driving shaft <NUM> connected to the other side large differential gear and the other side driving shaft <NUM> connected to the other side wheel adapter module <NUM>. The driving shaft <NUM> connected to the other side large differential gear is connected to one side of the spline collar, and the other side driving shaft <NUM> connected to the other side wheel adapter module <NUM> is connected to the other side of the spline collar, so that the one side driving shaft and the other side driving shaft can be formed in the same length and size.

The housing <NUM> of the differential brake unit <NUM> is adjusted in length so that the bearing insertion inner diameter portion <NUM> of the other side wheel adapter connection bridge <NUM> on which the spline collar <NUM> is mounted is located at a point where the other side driving shaft <NUM> and one side driving shaft <NUM> are equal in length.

Based on the power transmission housing, in which the differential gear unit <NUM> including: the motor driving gear <NUM> directly connected to the shaft of the motor <NUM> inside the one side power transmission housing <NUM> and the other side power transmission housing <NUM>; the reduction gear rotary shaft <NUM> disposed parallel with the rotary shaft <NUM> of the motor; a first reduction gear <NUM> of the reduction means <NUM> geared with the motor driving gear <NUM>; and the differential gear unit <NUM> including the crown wheel <NUM> of the differential unit formed to be geared with the second reduction gear <NUM>, the small differential gears <NUM> and <NUM> separating and transferring driving power of the crown wheel <NUM> to both sides, and the one side and the other side large differential gears <NUM> and <NUM> is embedded, the one side wheel adapter module <NUM> is coupled to one side of the power transmission housing and the differential brake unit <NUM> and the other side wheel adapter module <NUM> are coupled to the other side of the power transmission housing in a blocked form. Therefore, compared with the conventional housing formed integrally, the housing is separable and is lightweight, and the housing or the internal components can be partially replaced at the time of maintenance.

Moreover, the one side wheel adapter module <NUM> and the other side wheel adapter module <NUM> can be divided into the one side and the other side wheel adapters <NUM> and <NUM> respectively having the wheels mounted outside and the one side and the other side reduction units <NUM> and <NUM>, so the modules can be replaced or simply repaired during maintenance.

Claim 1:
A single drive axle brake for an electric forklift to transfer driving power of a motor to wheels disposed on right and left sides of driving shafts, the single drive axle brake comprising: a differential unit (<NUM>) for separating and transferring the driving power received from the motor (<NUM>) to both sides;
a differential gear unit (<NUM>) formed in the differential unit for distributing and transferring the driving power transferred from the motor to the wheels disposed on both sides; and
a brake unit (<NUM>) for restricting the differential gear unit (<NUM>), and
wherein the differential gear unit (<NUM>) comprises:
a crown wheel (<NUM>) of the differential unit receiving the driving power from the motor;
a differential gear case (<NUM>) coupled with the crown wheel (<NUM>);
a differential pinion gear mounted to be able to rotate and revolve with the differential gear case (<NUM>); and
differential side gears (<NUM>, <NUM>) geared with the differential pinion gear inside the differential gear case (<NUM>) coupled with the crown wheel (<NUM>) of the differential unit,
wherein the brake unit (<NUM>) is formed to restrict the differential gear case (<NUM>), and
wherein a power shaft (<NUM>) for transferring the driving power provided from the differential gear unit (<NUM>) is connected to the differential side gears (<NUM>, <NUM>) of the differential gear, and
wherein the brake unit (<NUM>) comprises: a main brake (<NUM>) for stopping the rotation of the differential gear case (<NUM>), and
whereby the brake unit (<NUM>) further comprises a subsidiary brake (<NUM>) for stopping the rotation of the power shaft (<NUM>), and
wherein the main brake (<NUM>) includes a main brake hub (<NUM>) and main discs (<NUM>) combined with the main brake hub, and main discs (<NUM>) are combined on the outer circumferential surface (<NUM>) of the main brake hub at regular intervals, and
wherein the subsidiary brake (<NUM>) comprises a subsidiary brake hub (<NUM>) and a subsidiary disc (<NUM>) coupled to the subsidiary brake hub, and
wherein the inner circumferential surface of the subsidiary brake hub is coupled to the outer circumferential surface of the power shaft, and the subsidiary disc (<NUM>) is coupled to the outer circumferential surface (<NUM>) of the subsidiary brake hub at regular intervals, characterised in that a portion of the inner circumferential surface of the main brake hub is joined to the outer circumferential surface (<NUM>) of the differential gear case.