| 1. | What is claimed is: Milling head with a built in automatic speed changer wherein the speed adjustment system (1) is mounted inside the milling head (2), near the spindle (3), wherein the head consists of two joints with tilted sides (2,4), so when they are set in motion they place the spindle in a horizontal, vertical or any other position within the 360 degrees and they can be operated manually or automatically, wherein the transmission for rotating the spindle (and for automatic head adjustment operations) is powered/driven by the main electric motor (5) of a variety of power and adjustable speeds, which through transmission (6) consisting of ball bearings, a shaft and gears leads to (passing through machine components and its head) the speed adjustment system located at the end portion of the head (2) where the spindle shaft (3) is located, wherein in this section, the last transmission bevel gear (7) is not in contact with the spindle (3) as is the case in standard milling heads, but rather through a movable coupling (8) consisting of a highspeed gear (9) and a lowspeed gear (10) which is directly connected to the spindle (presently switched off), actuates the first gear (11) of the speed adjustment system and here is where the first increase of speed is achieved, wherein the same speed adjustment system gear (11) is in direct contact with gear (12) which is connected tot he fixed spindle gear (13) and here is where the second speed acceleration takes place, wherein this connection provides for the high rotation speed of the milling head's spindle (3), which is controlled by the main motor (5). |
| 2. | The milling head of claim 1 wherein in order to achieve low speeds, a hydraulic, pneumatic or electric cylinder is used to move the mobile coupling (8) to a position which will switch off the highspeed gear (11), namely for turning off rotation multiplication, wherein at the same time the lowspeed gear (10) is connected tot he gear (14) which is fixed to the spindle (3) is achieved and consequently, lowspeed that is controlled by the main motor (5) is reached. |
| 3. | The milling head of claims 1 and 2, wherein in the first version a machine of 22 kw, max 6,000 spindle rotation with the torque of 600 Nm is used, namely a direct transmission motor, wherein in the applied design a 29.5 kw motor with the torque of 410 Nm, basic rotation 500 (Siemens catalogue), the relation between the drive wheels is 1.65 rotations, max. motor 7,000 has been used, which means that 7,000 : 1.65 = 6,034 rotations of all automations leading to the spindle, spindle torque 475 Nm. with minimal milling rotation power 431 and spindle rotation from 0 to 6,000, wherein the alternative is to mount the speed adjusters following the motor, but they need continuous lubrication under constant temperature and they only solve the problem of the size of the motor, wherein one must take into account the fact that the bearings onto which the ball bearings are mounted (they also must be of special material due to high speeds) must be designed in such a way as to permit the cooling liquid to pass through and thus its price will increase. |
| 4. | The milling head of claims 1 through 3, wherein in the second version the motor rotation rate is 8,000 : 3 (relation of the drive wheels) = max. 2,666 rotations of all automation except for the tool bearing the spindle, which solely has the ball bearings needed for high speeds 210 (motor torque) x 3 = 630 Nm on the spindle, minimum milling rotation power 333, wherein the spindle rotations from 0 to 9,400 (if a 10,000 rotation rate motor is installed that can reach 11,500 without causing any problems for the spindle because it is lubricated as is the entire head by spraying air + oil), wherein a better result has been reached by using the 22 kw ISO 50 spindle (the same system is applied for other head sizes) and component costs were decreased, wherein the head has been designed so that it can be mounted to the already existing machine tools, especially the older ones that most probably operate at smaller spindle rotation rates, wherein only smaller adjustments have been made in the connection between the two elements, wherein the speed adjuster consists of a pair of gears, which by means of a hydraulic cylinder is connected to the low or highspeed gear directly to the spindle and two sensors that are connected to the control instrument control this position. |
| 5. | The milling head of claims 1 through 4, wherein during the speed change by means of a cylinder, there is a neutral zone in which no gears are in contact with each other, and thus the switchof position is achieved. |
| 6. | The milling head of claims 1 through 5, wherein the hydraulic, pneumatic or electric cylinder, used for adjusting the speed, is controlled by means of two sensors that transmit a signal to the control instrument informing it of the head's speed. |
Field of Invention
This invention falls under the category of component parts or accessories that can be attached to the machine tool and/or some operative portion of the machine tool.
According to the International Patent Classification (IPC), the invention is classified under B23C 9/00. Technical Problem
This invention solves the technical problem posed by many: how to construct a milling machine that operates at a low rotation speed with corresponding torque and which at the same time can operate at high spindle rotation speeds needed for the finishing process. The presented technical problem is solved by the use of a mill head that has a built in automatic speed changer. Prior Art
The author of this invention has no knowledge of any same prior art that solves this technical problem.
The head designed according to this invention solves the problems that presently trouble machine tool producers i.e. it gives the possibility of constructing a machine that mills at low rotation speeds with the corresponding torque and which at the same time can operate at high spindle rotation speeds needed for finishing operations. Presently, this problem is partially solved by mounting a heavy weighted (390 kg) high powered and high torque motor that slightly reduces the relation between the drive wheels thus achieving a high rate of rotation (approx. 6000), but this causes problems: all units (automation) operate at high speed of rotation (6000), which causes overheating of bearings
(a cooler for cooling ball bearings must be installed); there are problems in maintaining machine tool's precision; mechanical components ware out acceleratedly - especially the head's bevel gears pairs; noise is a great problem; and maintaining the balance of the vertical shaft present a great problem.
Description of the Invention
According to this claim, the structure of the head enables the use of a smaller powered and sized spindle motor (180 kg), which as a consequence offers considerable savings potential/reduce costs. The units (automation) will operate maximally at a 3000 rotational speed with no need for cooling, and the only portion that will quickly rotate is the spindle head's shaft that is connected to the gearing, which will enable reaching rotational speeds greater than 6000 in the present version.
The invention is described in detail in: Figure 1. - drawing of the automation device type 1 Figure 2. - drawing of the automation device type 2 Figure 3. - cross-section with the speed setting zone Figure 4. - head detail
The speed adjustment system (1) is mounted inside the milling head (2), near the spindle (3). The head consists of two joints with tilted sides (2,4), so when they are set in motion they place the spindle in a horizontal, vertical or any other position within the 360 degrees. They can be operated manually or automatically.
The transmission for rotating the spindle (and for automatic head adjustment operations) is powered/driven by the main electric motor (5) (variety of power and adjustable speeds), which through transmission (6) consisting of ball bearings, a shaft and gears leads to (passing through machine components and its head) the speed adjustment system located at the end portion of the head (2) where the spindle shaft (3) is located. In this section, the last transmission bevel gear (7) is not in contact with the spindle (3) as is the case in standard milling heads, but rather through a movable coupling (8) consisting of a high-speed gear (9) and a low-speed gear (10) which is directly connected to the spindle (presently switched off) / actuates the first gear (11) of the speed adjustment system and here is where the first increase of speed is achieved. The speed adjustment system gear (11) is in direct contact with gear (12) which is connected to the fixed spindle gear (13)
and here is where the high speed takes place. This connection provides for the high rotation speed of the milling head's spindle (3), which is controlled by the main motor (5). In order to achieve low speeds, a hydraulic, pneumatic or electric cylinder is used to move the mobile coupling (8) to a position which will switch off the high-speed gear (11), namely for turning off rotation multiplication; at the same time the low-speed gear (10) is connected to the gear (14) which is fixed to the spindle (3) and thus direct connection of the bevel gear (7) with the spindle (3) is achieved. Consequently, low-speed that is controlled by the main motor (5) is reached.
During speed adjustment by means of a cylinder, there is a neutral zone in which no gears are in contact with each other, and thus the switch-off position is achieved. The hydraulic, pneumatic or electric cylinder, used for adjusting the speed, is controlled by means of two sensors that transmit a signal to the control instrument informing it of the head's speed.
In this position, the wearing out of the mechanical components is decreased because the spindle (3) is the only element that operates at high speeds. All the other components operate at low speeds because they are physically located in front of the speed adjustment system.
AUTOMAΗON VERSION. Type 1.
A machine of 22 kw, max 6,000 spindle rotation with the torque of 600
IMm. A direct transmission motor. At present, a 29.5 kw motor with the torque of 410 Nm, basic rotation 500 (Siemens catalogue), the relation between the drive wheels is 1.65 rotations, max. motor 7,000 (this is extra, the standard motor operates at 5000 rotations and thus the price will be almost double.
Therefore: 7,000 : 1.16 = 6034 rotations of all automations leading to the spindle, spindle torque 475 Nm. with minimal milling rotation power 431. Spindle rotation from 0 to 6,000. The alternative is to mount the speed adjusters following the motor, but they are costly and need continuous lubrication under constant temperature and they only solve the problem of the motor size. One
must take into account the fact that the bearings onto which the ball bearings are mounted (they must be of special material due to high speeds) must be
95 designed in such a way as to permit the cooling liquid to pass through and thus its price will increase. AUTOMAÏ€ON VERSION. Tvpe 2.
Motor rotation rate 8,000 : 3 (relation of the drive wheels) = max. 2,666 rotations of all automation except for the tool bearing the spindle which solely
100 has the ball bearings needed for high speeds - 210 (motor torque) x 3 = 630 Nm on the spindle, minimum milling rotation power 333.
Spindle rotations from 0 to 9,400 (if a 10,000 rotation rate motor is installed that can reach 11,500 without causing any problems for the spindle because it is lubricated as is the entire head by spraying air + oil.)
105 In this example, a better result has been reached by using the 22 kw ISO
50 spindle (the same system is applied for other head sizes) - component costs were decreased. The head has been designed so that it can be mounted to the already existing machine tools, especially the older ones that most probably operate at smaller spindle rotation rates. Only smaller adjustments have been
110 made in the connection between the two elements. The speed adjuster consists of a pair of gears, which by means of a hydraulic cylinder is connected to the low or high-speed gear directly to the spindle, and two sensors that are connected to the control instrument control this position.
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