TWI577908B - Gear transmission and drive unit - Google Patents

Description

Gear transmission and drive unit

The present application claims priority based on Japanese Patent Application No. 2011-246417 filed on Nov. 10, 2011. All contents of this application are incorporated by reference in the present specification.

The present invention relates to an eccentric rocking type gear transmission, and a drive unit using the same. The eccentric rocking type of gear transmission is also referred to as a cycloid drive.

There is known a gear transmission in which an external gear and an internal gear mesh with one side while one of them surrounds the other. In such a gear transmission, there is an outer gear wrap type and an inner gear wrap type, wherein the outer gear wrap type is that the outer gear meshes with the inner gear while encircling the inner side of the inner gear; the inner gear wrap type is the inner gear meshing side. The gear surrounds the outer gear on one side. Hereinafter, in order to simplify the specification, the technique disclosed in the present specification will be described using an external gear surround type. Also, it should be noted that the techniques disclosed in this specification are also applicable to the inner gear surround type.

The external gear surround type gear transmission generally has a carrier that is supported coaxially with the internal gear, a crank shaft supported by the carrier, and an external gear that is engaged with the eccentric body of the crankshaft. The internal gears are mostly formed on the inside of the outer casing. A hole is provided in the axial direction of the external gear, and the eccentric body is engaged with the hole. The outer gear and the inner gear mesh. The carrier corresponds to the output shaft of the gear transmission. The outer gear surrounds the inner circumference of the inner gear with the rotation of the crank shaft. Each outer gear rotates 1 In the circle, the carrier rotates corresponding to the difference in the scale of the external gear and the internal gear. The eccentric rocking type of gear transmission can achieve a very large gear ratio.

There is a type in a gear transmission having a plurality of crankshafts, and the motor and each of the crankshafts are coupled. An example of such a gear transmission is disclosed in Japanese Laid-Open Patent Publication No. 2009-159725 (Patent Document 1). The gear transmission of Patent Document 1 has a radial gap type motor coupled to each of the crank shafts.

In many gear transmissions, an alternating current synchronous motor driven by a UVW3 phase alternating current is often used as a radial gap motor. Many eccentric rocking gear transmissions having a plurality of crankshafts have three crankshafts, and the present specification is directed to this, providing a gear transmission that uses a single-phase motor instead of an alternating current synchronous motor driven by three-phase alternating current. This single-phase motor rotates smoothly due to its simple construction. In particular, the present invention provides a gear transmission that can smoothly rotate with an AC output inverter, and a drive unit using such a gear transmission.

The gear transmission disclosed in the present specification has three crankshafts and three single-phase claw pole motors. The three crankshafts are each connected by each of three single phase claw pole motors. The single-phase claw pole motor has a configuration in which the stator of the single-phase claw pole motor has a yoke of a pressing plate gold structure surrounding the coil. The comb-shaped poles extend alternately from both sides in the direction of the yoke axis. A rotor having a cylindrical multipole permanent magnet is disposed inside the stator. The shape of the magnetic pole is similar to that of a claw (claw, claw of a bird, crab, shrimp, etc.), and thus such a motor is called a claw pole type.

The three crankshafts are supported by a carrier and drive the same external gear. Therefore, the gear transmission disclosed in the present specification drives three identical single-phase claw pole motors to drive the same external gear. It is advantageous for the three single-phase claw pole motors to individually use the output of each phase of a UVW3 phase alternating current output inverter. The above gear transmission drives three single-phase claw pole motors simultaneously with one UVW3 phase AC output inverter, and transmits the torque to the same external gear through three crankshafts. Since the three single-phase claw motors are simultaneously driven by a 3-phase AC output inverter, the rotation of the three rotors is completely equal. Further, the torque is transmitted to the external gear through the three claw pole motors and the three crank shafts, so that the external gear rotates smoothly. Since the three claw pole motors can be driven by a 3-phase AC output inverter, the construction of the power system of the novel gear transmission disclosed in the present specification becomes simple. Due to the simple construction, a smooth rotating gear transmission can be obtained. Moreover, when there are a plurality of external gears, the three crankshafts simultaneously drive the respective external gears.

To simplify the construction, the single-phase claw pole motor can be coaxially fixed to the crankshaft. Further, for adjusting the geometric phase of the three claw pole motors, it is preferable that the rotor and the crank shaft are combined with a spline or a serration of a number of grooves (or keys) having a multiple of three. . Such a spline bond or a fine tooth combination has a rotation resolution of a multiple of three. The electrical phases of the three single-phase claw pole motors need to be 120 degrees apart. If the coupling mechanism of the rotor and the crankshaft has a rotational resolution of a multiple of three, it is advantageous to make the phase differences between each other equal.

As mentioned above, a gear transmission having three single-phase claw pole motors is advantageously driven by a three-phase alternating current output inverter. This manual Another aspect of the disclosed technology is to provide a gear transmission unit having the above-described three single-phase claw pole motors, and the aforementioned drive unit having an alternating current supply (electric phase on three single-phase claw pole motors) A 3-phase output inverter with a difference of 120 degrees).

Features of the gear transmission of the present invention and improvements thereof will be described in detail in the following embodiments.

1 is a cross-sectional view of the gear transmission 100 of the embodiment, and FIG. 2 is a plan view of the gear transmission 100 with the motor cover 40 removed as viewed in the direction of the axis CL of the gear transmission 100. For the sake of convenience, the gear transmission is referred to as "transmission device". 1 is a cross-sectional view taken along line A-A of FIG. 2.

The construction of the transmission 100 is schematically illustrated. The transmission 100 is an eccentric rocking type reducer in which three single-phase claw-pole motors 50a, 50b, and 50c are housed. The eccentric rocking type reducer can also be called a cycloidal speed reducer. The transmission 100, whose carrier 8 is supported by the outer casing 2 having the inner gear 28 inside, and the carrier 8 is also supported by three crank shafts 32 having a configuration for rotating the two outer gears 26. The two external gears 26 have engagement through holes 25, and the eccentric body 24 of the crankshaft engages with the engagement through holes 25. When the three crank shafts 32 rotate, the outer gear 26 meshes with the inner gear 28 while encircling the inner circumference of the inner gear. When the outer gear 26 is wound around one year, the carrier 8 only rotates the angle corresponding to the difference in the number of teeth of the internal gear 28 and the external gear 26. The carrier 8 corresponds to the output shaft of the transmission 100.

Three single-phase claw pole motors 50a, 50b and 50c are fixed to the carrier 8. Each of the rotor 54 and the three crankshafts 32 of each motor are coupled. Although FIG. 1 depicts only one crank shaft 32 and one claw pole motor 50a, as shown in FIG. 2, the transmission 100 has three crank shafts 32, and the single-phase claw pole motors 50a, 50b, and 50c are respectively cranked. Each of the shafts 32 is coupled. Hereinafter, the single-phase claw-pole motor will simply be referred to as a "CP motor." Further, the three CP motors 50a, 50b, and 50c are collectively referred to as "CP motor 50".

The CP motor 50 will be described. The rotor 54 of the CP motor 50 is coupled to one end of the crankshaft 32. The stator 52 of the CP motor 50 is fixed to the carrier 8. FIG. 3 illustrates an exploded view of the CP motor 50. The stator 52 is composed of a coil 62 and a pair of stator half cases 61 and 63 that house the coil 62. 3 is a simplified representation of the coil 62 in one loop. The stator half-shells 61, 63 have cam teeth 61a, 63a opposed to each other, respectively, and the pair of stator half-shells 61, 63 face each other, and the teeth of each other are alternately arranged in the circumferential direction. When a current flows through the coil 62 housed in the stator half covers 61 and 63, one of the teeth (for example, 61a) becomes the N pole, and the other tooth becomes the S pole (for example, 63a). That is, on the CP motor, a plurality of N magnetic poles and S magnetic poles are alternately arranged in the circumferential direction of the stator 52 by one coil 62. If the current of the coil 62 is reversed, the magnetic pole of the stator 52 is reversed. A plurality of permanent magnets are alternately arranged in the circumferential direction of the rotor 54. The CP motor 50 of the present embodiment is composed of a 24-pole stator 52 and a 12-pole rotor 54. When the magnetic pole of the stator 52 is reversed at a specific wavelength, the rotor 54 rotates. Therefore, this rotational speed is the wavelength synchronized to the pole inversion. The CP motor 50 can smoothly rotate the rotor in a single phase. The principle of the CP motor 50 is already known, so it is omitted. Further details.

A spline groove 66 is formed in the center of the rotor 54. The end of the crank shaft 32 is formed with a spline 67. The rotor 54 and the crankshaft 32 are coupled by spline bonding. The spline groove 66 has a groove of a multiple of three, and the spline 67 has a multiple of three. The splined groove 66 of Figure 3 has 12 slots and the splines 67 have 12 teeth, so this combination has a resolution of 30 degrees.

Fig. 4 schematically shows the phase relationship of the three CP motors 50a, 50b and 50c with each other. The angle between the triangular symbol Ar of the rotor 54 and the triangular symbol As shown in the stator 52 indicates the phase. In FIG. 4, the phase of the first CP motor 50a is 0 degrees, the phase of the second CP motor 50b is 120 degrees, and the phase of the third CP motor 50c is 240 degrees. Such three CP motors 50a, 50b, and 50c have an electrical phase difference of 120 degrees from each other. In order to make the phase differences of the three CP motors equal to each other, it is preferable that the rotational resolution of the combination of the crank shaft 32 and the rotor 54 is a multiple of three.

Three CP motors 50 drive the crankshaft 32, respectively. The three crank shafts 32 drive the two external gears 26 (refer to Fig. 1). As shown in FIG. 2, three CP motors 50 (three crank shafts 32) are arranged at equal intervals of an angle of 120 degrees around the axis CL of the transmission 100, and three CP motors 50 have an electrical phase of 120 degrees from each other. difference. Such a configuration causes the same external gear 26 to rotate smoothly. That is, the output shaft (carrier 8) of the transmission 100 is smoothly rotated by the above-described three CP motors 50.

If a three-phase AC output inverter is used, the output shaft (carrier 8) of the transmission 100 can be rotated more smoothly. Drive three CPs Motor 50 requires three single phase AC power. It is advantageous to drive only one 3-phase AC output inverter capable of outputting 3-phase AC power for driving the transmission 100 of the embodiment. Further, the three-phase AC output inverter which is a driver of the three-phase AC synchronous motor has some advantages, and various types thereof are widely used, and it is easy to obtain the type corresponding to the specifications of the transmission device 100.

FIG. 5 illustrates a power system block diagram of the drive unit 200, and the drive unit 200 is comprised of a transmission 100 and a 3-phase AC output inverter 74. The inverter 74 has switching circuits SW1 to SW6, and the switching circuits SW1 to SW6 are constituted by an anti-parallel connection of an insulated gate bipolar transistor (IGBT) and a freewheeling diode. The two switching circuits are connected in series between the positive line (P line) and the negative line (N line), and the output line extends from the point to the coil of the CP motor. The series connection of the two switching circuits has three groups, and the alternating currents of the U phase, the V phase, and the W phase are output from the midpoints of the respective groups. The single phase AC output of the UVW3 phase is supplied by the stator 52 of the three CP motors. Since the 3-phase AC outputs have a phase of 120 degrees from each other, it is advantageous to simultaneously rotate the three CP motors with a phase difference of 120 degrees. Further, since the inverter 74 requires DC input power, the output of the commercial AC power source 71 is converted into DC by the AC/DC rectifier 72, and this DC is input to the 3-phase AC output inverter 74. A capacitor 73 connected between the AC/DC rectifier 72 and the inverter 74 is provided to smooth the input current of the inverter 74.

Returning to Figure 1, additional features of the transmission 100 are described in detail. transmission The device 100 has a housing 2 and a carrier 8 and a crankshaft 32 and an external gear 26 and a CP motor 50. An inner gear 28 is provided on the inner side of the outer casing 2. A plurality of internal pin pins 30 are arranged at equal intervals in the circumferential direction inside the cylinder of the outer casing 2, and these internal tooth pins 30 constitute the internal gear 28.

The carrier 8 is supported by the outer casing 2 by a pair of angular ball bearings. The carrier 8 and the internal gear 28 are coaxially supported by the outer casing 2. The axis CL corresponds to the axis of the carrier 8. The axis CL also corresponds to the axis of the internal gear 28 (outer casing 2). The carrier 8 corresponds to the output shaft of the transmission 100. The carrier 8 is composed of a pair of disks (a first plate 8a and a second plate 8c) facing each other and a column 8b connecting the pair of disks. In the column 8b, the through hole 46 having the outer gear 26 deviated from the center passes.

An oil seal 6 is disposed between the outer casing 2 and the carrier 8. A motor cover 40 is attached to one end of the carrier 8 in the direction of the axis CL. The central through hole 12 is formed to penetrate the center of the carrier 8 and the motor cover 40, and the cylindrical tube 42 is fitted into the central through hole 12. The oil tube 41 is sealed between the cylindrical tube 42 and the carrier 8 (8c). By the motor cover 40, the oil seals 6, 41, and the cover 19 (described later), the space inside the casing in which the gear group is housed is sealed, and the lubricant is sealed.

The crankshaft 32 is supported by the carrier 8 by a pair of tapered roller bearings 23. The crank shaft 32 extends at a position offset from the axis CL in parallel with the axis CL. The symbol RL of the figure represents the center line of the crankshaft 32. The crank axle 32 has two eccentric bodies 24. The two eccentric bodies 24 are respectively engaged with the external gear 26. The two eccentric bodies 24 are eccentric with respect to the axis RL of the crankshaft 32 in opposite directions. Two eccentric bodies 24 are located between a pair of tapered roller bearings 23, thus The two eccentric bodies 24 do not change and can smoothly rotate.

A rotor 54 of the CP motor 50 is coupled to one end of the crankshaft 32, and an encoder 18 is attached to the other end. The other end of the crankshaft 32, i.e., the encoder 18, is covered by the cover 19 and isolated from the outside. Also, the encoder 18 is mounted on one of the three crankshafts 32. The other two crankshafts 32 are fitted with a brake (not shown).

The points of attention regarding the transmission 100 of the embodiment are described. The crankshaft 32 and the rotor 54 can also be joined by a serration instead of a spline. In the case of fine teeth, it is also preferable to make the number of grooves (or keys) of the serrations a multiple of three.

The transmission device 100 may include a crankshaft (drive crankshaft) that connects the three CP motors 50, and an auxiliary crankshaft (crankshaft to be driven) that is passively rotated by the rotational force of the external gear 26. The more the number of crankshafts, the more stable the rotation of the external gear 26.

Representative and non-limiting specific embodiments of the present invention have been described in detail with reference to the drawings. The detailed description is only intended to be illustrative of the preferred embodiments of the invention, and is not intended to limit the scope of the invention. Further, in addition to the additional features and inventions disclosed above, the present invention may be replaced by additional features disclosed above in order to provide an improved gear transmission or drive unit, or additional features of the above disclosure and the present invention may be shared.

In addition, the combination of features and engineering disclosed in the above detailed description is not intended to be a limitation of the invention. Further, in providing this hair The various features of the above-described representative embodiments, and the various features described in the independent and dependent claims, are not necessarily in accordance with the specific embodiments described herein or in the exemplified order. combination.

All the features described in the specification and/or the scope of the patent application are described in the specification and/or the scope of the patent application, and the disclosure of the application and the scope of the patent application are individually Content that is revealed independently of each other. In addition, the description of all numerical ranges and groups or collections is a limitation of the disclosure of the application and the scope of the patent application, and the numerical ranges, groups, and collections in the ranges are still within the scope of the present invention. .

2‧‧‧ Shell

4‧‧‧Bevel ball bearings

6‧‧‧ oil seal

8‧‧‧ Carrier

8a‧‧‧1st tablet

8b‧‧‧2nd tablet

8c‧‧‧Cylinder

12‧‧‧Central through hole

18‧‧‧Encoder

19‧‧‧ cover

23‧‧‧ Bearing

24‧‧‧Eccentric body

25‧‧‧Snap through hole

26‧‧‧External gear

28‧‧‧Internal gear

30‧‧‧ internal pin (pin)

32‧‧‧ crankshaft

40‧‧‧Motor cover

41‧‧‧ oil seal

42‧‧‧Cylinder tube

46‧‧‧through holes

50 (50a, 50b, 50c) ‧ ‧ single phase claw pole motor

52‧‧‧ Stator

54‧‧‧Rotor

61, 63‧‧‧ stator half cover

62‧‧‧ coil

66‧‧‧Spline slot

68‧‧‧ Spline

71‧‧‧Commercial AC power supply

72‧‧‧AC/DC rectifier

73‧‧‧ Capacitors

74‧‧‧3-phase AC output inverter

100‧‧‧Gear transmission

200‧‧‧ drive unit

SW1~SW6‧‧‧Switching Circuit

Figure 1 shows a cross-sectional view of a gear transmission.

Figure 2 is a plan view showing the gear transmission with the motor cover removed.

Figure 3 is an exploded perspective view of the motor.

4 is a schematic plan view showing the phase relationship of three motors with each other.

Figure 5 is a block diagram of a drive unit.

2‧‧‧ Shell

4‧‧‧angular ball bearing

6‧‧‧ oil seal

8‧‧‧ Carrier

8a‧‧‧1st tablet

8b‧‧‧2nd tablet

8c‧‧‧Cylinder

12‧‧‧Central through hole

18‧‧‧Encoder

19‧‧‧ cover

23‧‧‧ Bearing

24‧‧‧Eccentric body

25‧‧‧Snap through hole

26‧‧‧External gear

28‧‧‧Internal gear

30‧‧‧ internal pin (pin)

32‧‧‧ crankshaft

40‧‧‧Motor cover

41‧‧‧ oil seal

42‧‧‧Cylinder tube

46‧‧‧through holes

50a‧‧‧ single phase claw pole motor

52‧‧‧ Stator

54‧‧‧Rotor

100‧‧‧Gear transmission

CL‧‧‧ axis of gear transmission 100

Center line of RL‧‧‧ crankshaft 32

Claims (5)

A gear transmission device is an eccentric rocking gear transmission device comprising: three crank shafts; and three single-phase claw pole motors, wherein the three aforementioned single-phase claw pole motors are respectively connected to three of the aforementioned crankshafts, wherein each of the foregoing The rotors of the single-phase claw pole motors are respectively coaxially fixed to each of the aforementioned crankshafts, wherein each of the aforementioned rotors and each of the aforementioned crankshafts are coupled by splines or serrations, and the aforementioned splines or serrations have a multiple of three The number of grooves. The gear transmission of claim 1, wherein the electrical phase differences of the three aforementioned single-phase claw pole motors differ from each other by 120 degrees. A driving unit comprising: the gear transmission device according to claim 1; and a 3-phase AC output inverter for supplying an alternating current with a phase difference of 120 degrees to each of the three aforementioned single-phase claw-pole motors . A gear transmission device is an eccentric rocking gear transmission device comprising: three crank shafts; and three single-phase claw pole motors, wherein the three aforementioned single-phase claw pole motors are respectively connected to three of the aforementioned crankshafts, The electrical phase differences of the three aforementioned single-phase claw pole motors differ from each other by 120 degrees. A driving unit comprising: an eccentric rocking type gear transmission, the gear transmission device comprising three crank shafts; and three single-phase claw pole motors, wherein the three aforementioned single-phase claw pole motors are respectively connected to three of the aforementioned crankshafts; A 3-phase AC output inverter supplies an alternating current with a phase difference of 120 degrees to each of the three aforementioned single-phase claw-pole motors.