Special fiber flat drawing machine

Abstract

The utility model discloses a special fiber flat drawing machine which comprises a rack, a cold drawing disc component, a yarn feeding roller component, a hot drawing disc component, an oiling device and a winding component, a driving motor is arranged in the rack, the cold drawing disc component comprises a yarn drawing disc box body, a first transmission shaft and a cold drawing roller, and the cold drawing disc component is driven by the driving motor to rotate at the same speed. The yarn feeding roller component comprises a driving roller, a pressing roller and a yarn mover, the first oiling device comprises a first oiling frame and a first oiling nozzle, and the special structure of the oiling nozzle facilitates smooth flowing of oil and can regulate and control the oil outlet amount. The hot drafting disc component comprises four hot drafting roller assemblies, each hot drafting roller assembly comprises a plurality of hot drafting rollers with the adjustable rotating speed, and a heating layer and a temperature measuring module are arranged in each hot drafting roller. The second oiling device is similar to the first oiling device in structure but communicates with different oil tanks. According to the special fiber drafting, oiling and winding device, drafting, oiling and winding procedures of special fibers can be efficiently completed, and the fiber quality is improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to textile machinery technical field, concretely is a kind of special fiber flat drawing frame. BACKGROUND

[0002] Special fiber refers to fiber material with special physical and chemical properties, generally with high strength, high modulus, high temperature resistance, corrosion resistance, good impact resistance, strong designability and other characteristics, is widely used in various fields.In the production process of special fiber, hot drawing process is often needed, but the drawing technology generally used at present is to feed the unwound original wire into roller, cold disc pre-drawing, hot box+hot disc drawing setting, friction roller winding to complete winding, which leads to many problems in the drawing process, such as: it is difficult to realize the dynamic matching of temperature, tension and speed of drawing component, resulting in uneven fiber orientation;In the stretching process, the friction coefficient and thermal stability of fiber are difficult to control, and for special fiber that needs high-temperature oiling, additional oiling mechanism is needed, and the stretching mechanism and the oiling mechanism cooperate, not only the oiling uniformity is poor, and the oiling node is often not standardized, there is error, so that the quality of the output special fiber is uneven or the characteristics decrease, therefore, a kind of special fiber flat drawing frame is proposed, the drawing, oiling, setting, winding process of the processed wire is realized on the same equipment. SUMMARY

[0003] The present application provides a kind of special fiber flat drawing frame, including rack, cold drawing disc component, feed roller component, hot drawing disc component, oiling device and winding component, rack left and right sides are provided with rectangular mounting space, middle part is provided with longitudinal mounting plate, drive motor is arranged in rectangular mounting space, cold drawing disc component is arranged on the upper portion of mounting plate, cold drawing disc component includes first transmission shaft and several cold drawing rollers, feed roller component is arranged below cold drawing disc component, feed roller component includes driving roller and the pressure roller matched with driving roller, the pressure roller is provided with wire shifter above, hot drawing disc component is arranged below feed roller component, hot drawing disc component includes several hot drawing roller assemblies, hot drawing roller assembly includes several hot drawing rollers, cold drawing roller and hot drawing roller can rotate uniformly, winding component is arranged below hot disc drawing component, winding component includes wire guide and the winding cylinder matched with wire guide, pressure device is arranged below winding cylinder, oiling device includes first oiling device and second oiling device, first oiling device is arranged between feed roller component and hot drawing disc component, second oiling device is arranged between hot disc drawing component and winding component.

[0004] Preferably, the first oiling device includes a first oiling rack and a first oiling nozzle, the first oiling rack is connected to an oil tank, an oil channel is formed in the first oiling rack, and a plurality of first oiling nozzles are uniformly distributed on the upper part of the first oiling rack. The first oiling nozzle is an irregular three-dimensional structure arranged longitudinally, including a rectangular base and a convex platform with a triangular cross section. An inverted triangular oil outlet groove is arranged on the inclined surface of the convex platform with a triangular cross section.

[0005] Preferably, the second oiling device comprises a second oiling frame and a second oiling nozzle, the second oiling frame is connected to the oil tank, an oil channel is arranged inside the second oiling frame, a plurality of second oiling nozzles are uniformly distributed on the upper part, the second oiling nozzle is an irregular three-dimensional structure arranged longitudinally, comprising a rectangular base and a triangular-shaped boss, and an inverted triangular-shaped oil outlet groove is arranged on the inclined surface of the triangular-shaped boss.

[0006] Preferably, the first oiling nozzle and the second oiling nozzle on the first oiling device and the second oiling device correspond to each other, the first oiling nozzle and the second oiling nozzle are connected to different oil tanks and use different oil compositions inside, and the oil amount of the first oiling nozzle and the second oiling nozzle can be adjusted according to different types of fibers.

[0007] Preferably, the hot draft disc part comprises a first hot draft roller assembly, a second hot draft roller assembly, a third hot draft roller assembly and a fourth hot draft roller assembly, each hot draft roller assembly is provided with a plurality of hot draft rollers on the front surface, and the first hot draft roller assembly, the second hot draft roller assembly, the third hot draft roller assembly and the fourth hot draft roller assembly are respectively provided with a second transmission shaft, a third transmission shaft, a fourth transmission shaft and a fifth transmission shaft inside.

[0008] Preferably, the hot draft roller is in a cylindrical shape, comprising a transmission rod connected to the transmission shaft and a roller body fixed at the end of the transmission rod, a heating layer is arranged inside the roller body, a temperature measuring module is arranged on one side of the heating layer, and the heating layer and the temperature measuring module cooperate to adjust the temperature of the hot draft roller.

[0009] Preferably, the cold draft disc part is provided with a first transmission shaft inside, a plurality of cold draft rollers are arranged on the cold draft disc part, and a transmission shaft is arranged inside the cold draft roller and connected to the first transmission shaft through a gear.

[0010] Preferably, a plurality of groups of pressure rollers are arranged on the feed roller part, and a plurality of yarn shifters are arranged between the pressure rollers.

[0011] Preferably, the winding part comprises a sixth transmission shaft, a friction roller is sleeved on the sixth transmission shaft, a yarn guide is arranged above the friction roller, a winding drum is arranged on one side of the middle part of the friction roller and the yarn guide, the friction roller is in surface contact with the winding drum, a pressing device is arranged at the bottom of the winding drum, the pressing device comprises a bottom sleeve and a steel cable connected to the moving end of the sleeve, a pulley is arranged on the upper part of the steel cable, a counterweight is connected to the other end of the steel cable, and the bottom sleeve can always maintain contact pressure during work under the traction of the counterweight at the other end of the steel cable, so that the friction roller and the winding drum can always maintain contact.

[0012] Preferably, the number and position of the cold drawing roller, the yarn transfer device, the pressure roller, the hot drawing roller, the first oiling nozzle, the second oiling nozzle, the yarn guide and the winding drum are correspondingly arranged from top to bottom, and the first transmission shaft, the second transmission shaft, the third transmission shaft, the fourth transmission shaft, the fifth transmission shaft and the sixth transmission shaft are respectively connected with the driving motor, the driving motors are oppositely and spacedly arranged in the rectangular mounting space of the rack and can be individually controlled in rotation speed.

[0013] The application has the following characteristics and beneficial effects: the several groups of hot drawing roller assemblies are driven by separate driving motors, and each hot drawing roller is provided with a heating layer and a temperature measuring module, so that the temperature, tension and speed are dynamically matched, the fiber orientation is uniform, and the oiling devices are arranged before and after the hot drawing, the oiling uniformity is good and the oiling nodes are standardized during the operation of the drawing device and the oiling device, so that the stretched fiber quality is uniform and the characteristics are stable. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is the overall structure schematic view of the utility model;

[0015] Figure 2 is the overall structure front view of the utility model;

[0016] Figure 3 is the cold drawing disc component structure schematic view of the utility model;

[0017] Figure 4 is the feed roller component structure schematic view of the utility model;

[0018] Figure 5 is the first oiling device schematic view of the utility model;

[0019] Figure 6 is the second oiling device schematic view of the utility model Figure 5 is the structure enlarged schematic view of the upper A place;

[0020] Figure 7 is the hot disc drawing component structure schematic view of the utility model;

[0021] Figure 8 is the front view of Figure 7 ;

[0022] Figure 9 is the left view of Figure 7 ;

[0023] Figure 10 is the structure schematic view of the hot drawing roller of the utility model;

[0024] Figure 11 isFigure 10 is a left view of

[0025] Figure 12 is Figure 11 is a schematic view of A-A section of

[0026] Figure 13 is a schematic view of the second oiling device of the present application;

[0027] Figure 14 is a schematic view of the winding component of the present application;

[0028] Figure 15 is Figure 14 is a front view of

[0029] Figure 16 is a left view of Figure 13

[0030] Figure 17 is a fiber stretching flow chart of the present application.

[0031] 1-frame, 2-cold draft disc component, 201-first transmission shaft, 202-cold draft roller, 3-filament feeding roller component, 301-driving roller, 302-yarn shifter, 303-pressing roller, 4-first oiling device, 401-first oiling frame, 402-first oiling nozzle, 5-second oiling device, 501-second oiling frame, 502-second oiling nozzle, 6-hot draft disc component, 601-second transmission shaft, 602-third transmission shaft, 603-fourth transmission shaft, 604-fifth transmission shaft, 605-first hot draft roller assembly, 606-second hot draft roller assembly, 607-third hot draft roller assembly, 608-fourth hot draft roller assembly, 609-hot draft roller, 6091-transmission rod, 6092-roller body, 6093-heating layer, 6094-temperature measuring module, 7-winding component, 701-sixth transmission shaft, 702-yarn guide, 703-winding drum, 704-pressing device. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0033] As Figure 1 and Figure 2 ​As shown, a special fiber flat drawing machine, including frame 1, cold drawing disc component 2, feed roller component 3, hot drawing disc component 6, oiling device and winding component 7, frame 1 is provided with enclosed rectangular mounting space on the left and right, and the middle part is provided with longitudinal mounting plate, which cooperates with the rectangular mounting space on the left and right to form an integral mounting frame, and the driving motor is arranged in the rectangular mounting space on the left and right of frame 1, and the cold drawing disc component 2 and the feed roller component 3 are arranged in sequence from top to bottom on the mounting plate, the first oiling device 4 is arranged below the feed roller component 3, the hot drawing disc component 6 is arranged below the first oiling device 4, and the winding component 7 is arranged below the hot drawing disc component 6.

[0034] As shown in Figure 2 and Figure 3 , the cold drawing disc component 2 includes a drawing disc box, a first transmission shaft 201 is arranged in the drawing disc box, the driving motor connected with the first transmission shaft 201 is arranged in the rectangular mounting space on the left side of the frame 1, six cold drawing rollers 202 are arranged side by side on the shell, a transmission shaft is arranged inside the cold drawing roller 202 and connected with the gear of the first transmission shaft 201, the first transmission shaft 201 is driven to rotate by the driving motor, so as to drive the six cold drawing rollers 202 to rotate at the same speed.

[0035] As shown in Figure 2 and Figure 4 , the feed roller component 3 is arranged below the cold drawing disc component 2, the feed roller component 3 includes a driving roller 301 horizontally arranged in the middle part of the frame 1 and a pressure roller 303 arranged above the driving roller, a transmission shaft is arranged on one side of the driving roller 301 and connected with the driving motor on one side of the frame 1, so that the pressure roller 303 can rotate under the drive of the motor, the pressure roller 303 is provided with six, a yarn shifter 302 is arranged above each pressure roller 303, the end of the yarn shifter 302 is annular, and the end has an upward inclination which protrudes out of the pressure roller 303, the yarn shifter 302 is driven by a transmission device to move slowly and reciprocally, an elastic rubber layer is arranged on the pressure roller 303 to increase the friction between the roller and the yarn, and through the cooperation of the pressure roller 303 and the driving roller 301, it is ensured that the feed roller component 3 can stably and efficiently complete the transmission task of the yarn, and provide a good basis for the subsequent textile processing link.

[0036] As shown in Figure 2 , Figure 5 and Figure 6 , the first oiling device 4 is arranged below the feed roller component 3, the first oiling device 4 includes a first oiling frame 401 with an oil channel arranged inside, the first oiling frame 401 is connected with an oil tank, the oil channel is arranged inside the first oiling frame 401, so that the oil can circulate in the first oiling frame 401 and the oil tank, and six first oiling nozzles 402 are arranged on the front of the first oiling frame 401, as shown in Figure 6As shown, the first oiling nozzle 402 is an irregular three-dimensional structure arranged longitudinally, including a rectangular base and a triangular-shaped boss, and a reverse triangular-shaped oil outlet groove is arranged on the inclined surface, so that the oil can smoothly enter the triangular area from the opening during oiling, which is conducive to the smooth flow of oil between the inclined surface and the triangular area, and the first oiling nozzle 402 can regulate the oiling amount according to the different requirements of special fibers.

[0037] As shown in Figure 1 , Figure 7 , Figure 8 and Figure 9 , a hot plate drafting component 6 is arranged below the first oiling frame 201, which includes a first hot drafting roller assembly 605, a second hot drafting roller assembly 606, a third hot drafting roller assembly 607 and a fourth hot drafting roller assembly 608. Each hot drafting roller assembly includes a drafting disc box and six hot drafting rollers 609, and the hot drafting rollers 605 on the first hot drafting roller assembly 605, the second hot drafting roller assembly 606, the third hot drafting roller assembly 607 and the fourth hot drafting roller assembly 608 are longitudinally aligned. Each row of hot drafting roller assemblies is stepped and protrudes step by step, and the first hot drafting roller assembly 605, the second hot drafting roller assembly 606, the third hot drafting roller assembly 607 and the fourth hot drafting roller assembly 608 are connected with the second transmission shaft 601, the third transmission shaft 602, the fourth transmission shaft 603 and the fifth transmission shaft 604 in turn. The end of the transmission shaft of each row of hot drafting roller assemblies is connected with the driving motor inside the two sides of the rack 1, and the driving motors are arranged in opposite directions and at intervals, so that the overall balance of the equipment is stronger. Different driving motors can provide driving force for each group of hot drafting roller assemblies at different speeds, and the hot drafting rollers 605 on each group of hot drafting roller assemblies can be adjusted to different drafting multiples suitable for various special fibers through different speeds.

[0038] As shown in Figure 10 , Figure 11 and Figure 12 , the hot drafting roller 609 is in a cylindrical shape, including a transmission rod 6091 connected with the transmission shaft and a roller body 6092 fixed at the end of the transmission rod 6091. The roller body 6092 is rotated by the transmission rod 6091. A heating layer 6093 is arranged inside the roller body 6092, and a temperature measuring module 6094 is arranged on one side of the heating layer 6093. The heating layer 6093 and the temperature measuring module 6094 cooperate to adjust the temperature of the hot drafting roller 609.

[0039] As shown in Figure 2 , Figure 13As shown, a second oiling device 5 is arranged below the hot drawing disc 6, the second oiling device 5 comprises a second oiling frame 501 with oil channels arranged inside, the second oiling frame 501 is communicated with a different oil tank from the first oiling frame 401 and different oil agent is used in the oil tank, and six second oiling nozzles 502 are arranged on the front side, the second oiling nozzles 502 have the same structure as the first oiling nozzles 402.

[0040] As shown in Figure 14 , Figure 15 and Figure 16 , the winding component 7 comprises a sixth transmission shaft 701, a yarn guide 702, a winding drum 703 and a pressing device 704, the yarn guide 702 is arranged above the sixth transmission shaft 701, the yarn guide 702 can guide the special fiber to be wound to be uniformly wound on the winding drum 703, a friction roller is sleeved on the sixth transmission shaft 701, the friction roller is in contact with the winding drum 703, when the friction roller is rotated by the sixth transmission shaft 701, the friction roller drives the winding drum 703 to rotate by friction force, in the rotating process, the yarn guide 702 guides the fiber to be uniformly wound on the winding drum 703, the winding drum 703 is equipped with the pressing device 704, the pressing device 704 comprises a bottom sliding sleeve and a steel cable connected to the moving end of the sliding sleeve, two pulleys are arranged on the upper part of the steel cable, a counterweight is arranged on the other end of the steel cable, by the gravity of the counterweight, the sliding sleeve can always keep the contact pressure state in the working state, the sliding sleeve drives the winding drum 703 to always be close to the friction roller on the sixth transmission shaft 701, and the size and shape of the winding are accurately controlled.

[0041] As shown in Figure 16As shown, in use, the special fiber to be stretched is first passed through the yarn shifter 302 and enters the feed roller component 3, and the fiber is drawn into the active roller 301 and the compression roller 303 by the feed roller component 3. When the feed roller component 3 is working, the yarn shifter 302 makes a slow transverse reciprocating motion. Before the fiber is stretched, the first oiling nozzle 402 on the first oiling device 4 is used for pre-stretching oiling. Then the fiber to be stretched is wound on the hot draft disc component 6 step by step. After 3 to 5 turns on the first hot draft roller assembly 605, the fiber is wound on the second hot draft roller assembly 606. Then the fiber is wound on the third hot draft roller assembly 607 and the fourth hot draft roller assembly 608 in turn. Since the drive motors of the four hot draft roller assemblies are independently arranged, the rotation speed of the hot draft roller 609 can be adjusted by adjusting the rotation speed of the motor, so as to adjust the stretching amplitude between the hot draft roller assemblies. After the special fiber is stretched by the hot draft process, the second oiling nozzle 502 on the second oiling device 5 is used for secondary oiling, further enhancing the fiber toughness. At this time, the fiber is wound around the bottom pulley and directly upward to the cold draft disc component 2 for cold drawing. After cold drawing, the special fiber passes through the yarn guide 702 of the winding component 7, and the fiber is distributed to the winding drum 703 by the yarn guide 702 for winding. During the winding process, the fiber on the winding drum 703 becomes more and more, so that the winding drum 703 gradually protrudes. At this time, the pressure device 704 limits the winding drum 703 through the steel cable connected to the sliding sleeve and the counterweight behind the steel cable, so that the winding surface is always in frictional contact with the sleeve outside the sixth transmission shaft 701, ensuring accurate control of the shape and size of the fiber roll during winding.

Claims

1. A special fiber flat drawing machine comprising a frame (1), a cold drawing disk assembly (2), a godet roller assembly (3), a hot drawing disk assembly (6), an oiling device and a winding assembly (7), characterized in that: The rack (1) is provided with rectangular mounting spaces on the left and right sides, and a longitudinal mounting plate is arranged in the middle. A driving motor is arranged in the rectangular mounting space. A cold drawing disc component (2) is arranged on the upper part of the mounting plate. The cold drawing disc component (2) comprises a first transmission shaft (201) and a plurality of cold drawing rollers (202). A wire feeding roller component (3) is arranged below the cold drawing disc component (2). The wire feeding roller component (3) comprises a driving roller (301) and a pressure roller (303) matched with the driving roller (301). A wire shifter (302) is arranged above the pressure roller (303). A hot drawing disc component (6) is arranged below the wire feeding roller component (3). The hot drawing disc component (6) comprises a plurality of hot drawing roller assemblies. Each hot drawing roller assembly comprises a plurality of hot drawing rollers (609). The cold drawing rollers (202) and the hot drawing rollers (609) can rotate at a uniform speed. A winding component (7) is arranged below the hot drawing disc component (6). The winding component (7) comprises a wire guide (702) and a winding drum (703) matched with the wire guide (702). A pressing device (704) is arranged below the winding drum (703). The oiling device comprises a first oiling device (4) and a second oiling device (5). The first oiling device (4) is arranged between the wire feeding roller component (3) and the hot drawing disc component (6). The second oiling device (5) is arranged between the hot drawing disc component (6) and the winding component (7).

2. A special fibre flat drawing machine as claimed in claim 1, characterized in that, The first oiling device (4) comprises a first oiling frame (401) and a first oiling nozzle (402). The first oiling frame (401) is connected to an oil tank. An oil channel is formed in the first oiling frame (401). A plurality of first oiling nozzles (402) are uniformly distributed on the first oiling frame (401). The first oiling nozzle (402) is an irregular three-dimensional structure arranged in a longitudinal direction. The first oiling nozzle (402) comprises a rectangular base and a protrusion with a triangular cross section. An inverted triangular oil outlet groove is arranged on the inclined surface of the protrusion with a triangular cross section.

3. A special fibre flat drawing machine as claimed in claim 2, characterized in that, The second oiling device (5) comprises a second oiling frame (501) and a second oiling nozzle (502). The second oiling frame (501) is connected to an oil tank. An oil channel is formed in the second oiling frame (501). A plurality of second oiling nozzles (502) are uniformly distributed on the second oiling frame (501). The second oiling nozzle (502) is an irregular three-dimensional structure arranged in a longitudinal direction. The second oiling nozzle (502) comprises a rectangular base and a protrusion with a triangular cross section. An inverted triangular oil outlet groove is arranged on the inclined surface of the protrusion with a triangular cross section.

4. A special fibre flat drawing machine as claimed in claim 3, characterized in that, The first oiling nozzle (402) and the second oiling nozzle (502) on the first oiling device (4) and the second oiling device (5) correspond to each other. The first oiling nozzle (402) and the second oiling nozzle (502) are connected to different oil tanks and use different oil components. The oil amount of the first oiling nozzle (402) and the second oiling nozzle (502) can be adjusted according to different types of fibers.

5. A special fibre flat drawing machine as claimed in claim 4, characterized in that, The hot drawing disc component (6) comprises a first hot drawing roller assembly (605), a second hot drawing roller assembly (606), a third hot drawing roller assembly (607) and a fourth hot drawing roller assembly (608), each of which is provided with a plurality of hot drawing rollers (609) on the front side, and the first hot drawing roller assembly (605), the second hot drawing roller assembly (606), the third hot drawing roller assembly (607) and the fourth hot drawing roller assembly (608) are respectively provided with a second transmission shaft (601), a third transmission shaft (602), a fourth transmission shaft (603) and a fifth transmission shaft (604).

6. A special fibre flat drawing machine as claimed in claim 5, characterized in that, The hot drawing roller (609) is in a cylindrical shape, comprising a transmission rod (6091) connected with the transmission shaft and a roller body (6092) fixed at the end of the transmission rod (6091), and a heating layer (6093) is arranged inside the roller body (6092), and a temperature measuring module (6094) is arranged on one side of the heating layer (6093), and the heating layer (6093) and the temperature measuring module (6094) can adjust the temperature of the hot drawing roller (609).

7. A special fibre flat drawing machine as claimed in claim 6, characterized in that, The cold drawing disc component (2) is internally provided with a first transmission shaft (201), and a plurality of cold drawing rollers (202) are arranged on the cold drawing disc component (2), and a transmission shaft is arranged inside the cold drawing roller (202) and connected with the first transmission shaft (201) through a gear.

8. A special fibre flat drawing machine as claimed in claim 7, characterized in that, A plurality of groups of compression rollers (303) are arranged on the yarn feeding roller component (3), and a plurality of yarn shifting devices (302) are arranged between the compression rollers (303).

9. A special fibre flat drawing machine as claimed in claim 8, characterized in that, The winding component (7) comprises a sixth transmission shaft (701), a friction roller is sleeved on the sixth transmission shaft (701), a yarn guide (702) is arranged above the friction roller, a winding drum (703) is arranged on one side of the middle part of the friction roller and the yarn guide (702), the friction roller is in surface contact with the winding drum (703), a pressing device (704) is arranged at the bottom of the winding drum (703), the pressing device (704) comprises a bottom sliding sleeve and a steel cable connected to the moving end of the sliding sleeve, a pulley is arranged on the upper part of the steel cable, a counterweight is connected to the other end of the steel cable, and the bottom sliding sleeve can always maintain contact pressure during work under the traction of the counterweight at the other end of the steel cable, so that the friction roller and the winding drum (703) can always maintain contact.

10. A special fibre flat drawing machine as claimed in claim 9, characterized in that, The number and position of the cold drawing roller (202), the yarn shifting device (302), the compression roller (303), the hot drawing roller (609), the first oil feeding nozzle (402), the second oil feeding nozzle (502), the yarn guide (702) and the winding drum (703) are correspondingly arranged from top to bottom, one side of the first transmission shaft (201), the second transmission shaft (601), the third transmission shaft (602), the fourth transmission shaft (603), the fifth transmission shaft (604) and the sixth transmission shaft (701) is respectively connected with a driving motor, the driving motors are oppositely and intervaliy arranged in the rectangular mounting space of the rack (1) and can be individually controlled in rotation speed.

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