JP2019011798A - Reduction gear - Google Patents

Abstract

To provide a reduction gear excellent in mountability.SOLUTION: This reduction gear 1 comprises: an output shaft 2 in which a plurality of teeth 2a are formed at an external peripheral face; an eccentric member 3 arranged at an outside-diameter side with respect to the output shaft 2, and having an internal peripheral face which is decentered to the output shaft 2; a plurality of rollers 6 arranged between the output shaft 2 and the eccentric member 3; and a cage 7 for rotatably holding the rollers 6. Everytime the eccentric member 3 rotates one round, the rollers 6 push output shaft 2, the output shaft 2 is rotated to a peripheral direction by an amount of one tooth, and the output shaft 2 is thereby decelerated in speed with respect to the eccentric member 3, and rotates.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a reduction gear.

  Conventionally, as a reduction gear mounted on vehicles, industrial robots, etc., a roller is sequentially engaged with a plurality of teeth formed on the inner peripheral surface of an internal gear, and the rotation of the input shaft is decelerated and transmitted to the output shaft. A roller-type speed reducer is known.

  Generally, this type of reducer includes an input shaft 100 having an eccentric portion 100a on the outer peripheral surface, an internal gear 200 having a plurality of teeth formed on the inner peripheral surface, and an internal gear, as shown in the example shown in FIG. 200, a plurality of rollers 300 disposed between the inner peripheral surface of the input shaft 100 and the eccentric portion 100a of the input shaft 100, a holder 400 that rotatably holds the roller 300, and an output shaft that is configured integrally with the holder 400. 500 (see Patent Document 1). When a driving force is input to the input shaft 100 from a driving source such as an electric motor and the input shaft 100 is rotated, the roller 300 is sequentially engaged with the teeth of the internal gear 200 by the rotation of the eccentric portion 100a. As the roller 300 moves by one tooth in the circumferential direction for every rotation, the output shaft 500 rotates at a reduced speed with respect to the input shaft 100.

JP 62-93565 A

  In the conventional configuration as shown in FIG. 12, when the electric motor is connected to the speed reducer, a method of connecting the output shaft of the electric motor in series with the input shaft of the speed reducer is generally employed. However, when the speed reducer and the electric motor are connected in this way, the size of the entire device in a state in which they are connected increases in the axial direction, and there is a problem in mountability with respect to the vehicle and various devices.

  Then, an object of this invention is to provide the reduction gear which is excellent in mountability.

  As a technical means for achieving the above-mentioned object, the present invention includes an output shaft having a plurality of teeth on the outer peripheral surface, and an inner shaft arranged on the outer diameter side of the output shaft and eccentric with respect to the output shaft. An eccentric member having a peripheral surface, a plurality of rollers disposed between the output shaft and the eccentric member, and a cage for rotatably holding the roller, each time the eccentric member rotates, the roller outputs The output shaft is decelerated and rotated with respect to the eccentric member by pushing the tooth gap of the shaft and rotating the output shaft in the circumferential direction by one tooth.

  In the speed reducer according to the present invention, the eccentric member to which the driving force is input is disposed on the outer diameter side of the output shaft, so that the speed reducer is disposed on the inner diameter side of the rotary drive unit such as the hollow motor or the hollow shaft. Easy to place. In other words, when the eccentric member to which the driving force is input is located on the outer diameter side of the output shaft, when the reduction gear is disposed on the inner diameter side of a hollow motor, a hollow shaft, etc., the driving force is transmitted from these to the reduction gear. The structure can be easily realized. On the other hand, in the conventional configuration, since the input shaft is arranged on the inner diameter side of the internal gear, the reduction gear is arranged in the hollow motor, and driving force is input from the outer diameter side hollow motor to the inner diameter side input shaft. Difficult to do. Thus, in the speed reducer according to the present invention, the output shaft is disposed on the inner diameter side and the eccentric member is disposed on the outer diameter side so that the driving force can be easily input from the outer diameter side. It becomes easy to arrange on the inner diameter side of a hollow motor or a hollow shaft. As a result, the speed reducer need not be arranged in series in the axial direction with respect to the drive source as in the prior art, and the axial size when the speed reducer and the drive source are connected can be suppressed. And mountability on various devices is improved.

  Furthermore, the speed reducer according to the present invention includes a fixed shaft and a plurality of rollers disposed between the fixed shaft and the eccentric member in addition to the above configuration, thereby realizing a high output configuration with a high reduction ratio. it can. The fixed shaft is a member provided with a plurality of teeth on the outer peripheral surface, arranged coaxially with the output shaft on the inner diameter side of the eccentric member, and fixed so as not to rotate. The roller disposed between the fixed shaft and the eccentric member and the roller disposed between the output shaft and the eccentric member are rotatably held by a cage. In this case, each time the eccentric member makes one rotation, the roller disposed between the fixed shaft and the eccentric member moves in the circumferential direction by one tooth with respect to the fixed shaft, so that the cage moves relative to the eccentric member. To slow down. Further, the roller between the output shaft and the eccentric member pushes the tooth groove of the output shaft to rotate the output shaft in the circumferential direction by one tooth, so that the output shaft rotates at a reduced speed with respect to the eccentric member. Thus, by adopting a configuration in which rotation is transmitted by decelerating between the fixed shaft and the roller and between the output shaft and the roller, it is possible to realize a small reduction gear with high output.

  By providing an engaging portion that engages with the inner peripheral surface of the rotation drive portion on the outer peripheral surface of the eccentric member, the eccentric member rotates when the speed reducer is disposed on the inner diameter side of a hollow motor, a hollow shaft, or the like. It can be configured to engage with the inner peripheral surface of the drive unit and rotate integrally with the rotation drive unit.

  According to the present invention, the speed reducer can be easily arranged on the inner diameter side of the drive source or the power transmission member, and the mountability is improved.

It is a longitudinal section of a reduction gear concerning one embodiment of the present invention. It is a disassembled perspective view of the reduction gear shown in FIG. It is an AA arrow directional cross-sectional view in FIG. It is a longitudinal cross-sectional view of the electric actuator which mounted the reduction gear shown in FIGS. 1-3 in an electric motor. It is a disassembled perspective view of the electric actuator shown in FIG. It is a longitudinal cross-sectional view of the reduction gear which concerns on other embodiment of this invention. It is a disassembled perspective view of the reduction gear shown in FIG. FIG. 7 is a cross-sectional view taken along line B-B in FIG. 6. It is CC sectional view taken on the line in FIG. It is a longitudinal cross-sectional view of the electric actuator which mounted the reduction gear shown in FIGS. 6-9 in the electric motor. It is a disassembled perspective view of the electric actuator shown in FIG. It is a longitudinal cross-sectional view of the conventional reduction gear.

  Hereinafter, the present invention will be described with reference to the accompanying drawings. In the drawings for explaining the present invention, components such as members and components having the same function or shape are denoted by the same reference numerals as much as possible, and once described, the description will be given. Omitted.

  FIG. 1 is a longitudinal sectional view of a reduction gear according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of the reduction gear shown in FIG. 3 is a cross-sectional view taken along line AA in FIG.

  As shown in FIGS. 1 to 3, the speed reducer 1 according to this embodiment includes an output shaft 2, an eccentric member 3 that is eccentric with respect to the output shaft 2, and a needle as a bearing member on the inner periphery of the eccentric member 3. A cylindrical member 5 arranged via a tapered roller bearing 4, a plurality of rollers 6 arranged between the inner peripheral surface of the cylindrical member 5 and the output shaft 2, and a cage for rotatably holding each roller 6. 7 and the casing 8 for housing them are the main components.

  The output shaft 2 is a columnar or cylindrical member, and is disposed at the center (inner diameter side) in the casing 8 formed in a bottomed cylindrical shape. A plurality of teeth 2a are provided at equal intervals in the circumferential direction on the outer peripheral surface of the output shaft 2, and a curved tooth groove 2b (see FIG. 3) is formed between the teeth 2a.

  The eccentric member 3 is an annular member whose inner circumferential surface is eccentric in the radial direction by a distance Y with respect to the central axis (rotating shaft) of the output shaft 2. The eccentric member 3 is disposed on the outer diameter side of the output shaft 2 and is rotatably accommodated in the casing 8.

  The cylindrical member 5 is a member in which the outer peripheral surface and the inner peripheral surface are formed with smooth curved surfaces having no irregularities over the entire circumference. The cylindrical member 5 is disposed on the inner periphery of the eccentric member 3 via the needle roller bearing 4 and is rotatably supported.

  The plurality of rollers 6 are disposed between the teeth 2 a or tooth grooves 2 b provided on the output shaft 2 and the inner peripheral surface of the cylindrical member 5. Each roller 6 is accommodated one by one in a plurality of pockets 7a formed at equal intervals in the circumferential direction of the cage 7, and is held so as to be movable in the radial direction within the pocket 7a. The cage 7 is formed in a cylindrical shape, and one end side in the axial direction (the right end side in FIG. 1) is fitted to the casing 8. Thereby, the cage 7 is fixed so as not to rotate with respect to the casing 8.

  Here, since the cylindrical member 5 is disposed via the needle roller bearing 4 with respect to the inner peripheral surface of the eccentric member 3, the inner peripheral surface of the cylindrical member 5 is also relative to the central axis of the output shaft 2. It is arranged eccentrically. Therefore, as shown in FIG. 3, the center Q of the circle passing through the central axis of each roller 6 arranged on the inner peripheral surface of the cylindrical member 5 is also decentered by the distance Y in the radial direction with respect to the central axis O of the output shaft 2. Yes. For this reason, the roller 6 is located close to and engaged with the tooth groove 2b of the output shaft 2 in a part of the circumferential direction on the inner peripheral surface of the cylindrical member 5 (lower side in FIG. 3). In the opposite position (upper side in FIG. 3), it is spaced from the tooth groove 2b of the output shaft 2 and is not engaged.

The number of rollers 6 is appropriately determined according to the reduction ratio of the output shaft 2. Specifically, if the reduction ratio of the output shaft 2 is i, the number of teeth 2a is one more than the reduction ratio i of the output shaft 2 (i + 1).
Or it is set to a number (i-1) less by one. Further, the number of rollers 6 is set to a divisor of the reduction ratio i of the output shaft 2.

  Then, operation | movement of the reduction gear which concerns on this embodiment is demonstrated.

  When driving force is input from the outside and the eccentric member 3 rotates, the roller 6 reciprocates in the radial direction with respect to the output shaft 2 accordingly. The roller 6 presses the wall of the tooth groove 2b of the output shaft 2 by the reciprocating motion in the radial direction, so that the output shaft 2 is rotated by receiving a circumferential force. Thereby, the output shaft 2 rotates in the circumferential direction by one tooth of the output shaft 2 every time the eccentric member 3 rotates, and rotates at a reduced speed with respect to the eccentric member 3. At this time, assuming that the number of teeth of the output shaft is z, the output shaft rotates 1 / z of one tooth while the eccentric member rotates once, so the reduction ratio becomes z which is the reciprocal of the rotational speed.

  Hereinafter, the point that the speed reducer according to the present embodiment is excellent in mountability will be described.

  4 is a longitudinal sectional view of an electric actuator in which the reduction gear according to the present embodiment is mounted in an electric motor, and FIG. 5 is an exploded perspective view of the electric actuator shown in FIG.

  As shown in FIGS. 4 and 5, the electric actuator 9 includes a hollow electric motor 11, a speed reducer 1 disposed in the electric motor 11, and a casing 10 that accommodates them. The casing 10 of the electric actuator 9 is different from the casing 8 of the speed reducer 1 shown in FIGS. In the electric actuator 9, a casing 10 having an inner diameter larger than this is used instead of the casing 8 shown in FIGS. 1 to 3 so that the electric motor 11 can be arranged on the outer periphery of the speed reducer 1 (excluding the casing 8). ing.

  The electric motor 11 is a radial gap type hollow motor having a stator 12 fixed to the casing 10 and a rotor 13 as a rotation drive unit facing the stator 12 in the radial direction with a gap. The stator 12 includes a stator core made of a plurality of electromagnetic steel plates laminated in the axial direction, a bobbin made of an insulating material attached to the stator core, and a stator coil wound around the bobbin. The rotor 13 includes an annular rotor core (rotor inner) and a plurality of magnets attached to the rotor core.

  The reduction gear 1 is disposed in a motor core composed of a stator 12 and a rotor 13, and the eccentric member 3 is fixed to the inner peripheral surface of the rotor 13. Specifically, a plurality of concave engaging portions 3 a are provided on the outer peripheral surface of the eccentric member 3, and the convex engaging portions 13 a provided on the inner peripheral surface of the rotor 13 are engaged with the engaging portions 3 a. Thus, the eccentric member 3 is fixed so as not to rotate with respect to the inner peripheral surface of the rotor 13. Of course, the concave-convex relationship between the eccentric member 3 and the engaging portions 3a, 13a of the rotor 13 may be reversed. When the electric motor 11 is driven and the rotor 13 rotates, the eccentric member 3 rotates integrally with the rotor 13, and the output shaft 2 rotates at a reduced speed relative to the eccentric member 3 by the operation of the speed reducer 1 described above. .

  Thus, in the speed reducer according to the present embodiment, it is possible to input driving force from the electric motor 11 to the speed reducer 1 simply by fixing the eccentric member 3 so as to rotate integrally with the rotor 13. is there. That is, since the eccentric member 3 to which the driving force is input is on the outer diameter side of the speed reducer 1, the drive from the electric motor 11 to the speed reducer 1 when the speed reducer 1 is disposed in the hollow electric motor 11. A force transmission structure can be easily realized. On the other hand, in the conventional configuration shown in FIG. 12, since the input shaft 100 is disposed on the inner diameter side of the internal gear 200, the reduction gear is disposed in the hollow motor and the inner diameter side input from the outer diameter side hollow motor is performed. It is difficult to input driving force to the shaft. On the other hand, in the reduction gear according to the present embodiment, the output shaft 2 is arranged on the inner diameter side and the eccentric member 3 is arranged on the outer diameter side, so that the driving force can be easily input from the outer diameter side. .

  As described above, according to the configuration according to the present embodiment, it is easy to dispose the speed reducer on the inner diameter side of the rotary drive unit such as the hollow motor or the hollow shaft, and the speed is reduced with respect to the drive source as in the past. Since the machines do not have to be arranged in series in the axial direction, the size in the axial direction when the speed reducer and the drive source are connected can be suppressed. Thereby, the mounting property of the reduction gear with respect to a vehicle, various apparatuses, etc. improves. For example, the speed reducer according to the present invention can be applied to a variable valve timing device that changes the opening / closing timing of one or both of an intake valve and an exhaust valve of an automobile engine.

  FIG. 6 is a longitudinal sectional view of a reduction gear according to another embodiment of the present invention, and FIG. 7 is an exploded perspective view of the reduction gear shown in FIG. 8 is a cross-sectional view taken along line BB in FIG. 6, and FIG. 9 is a cross-sectional view taken along line CC in FIG.

  As shown in FIGS. 6 to 9, in the speed reducer 1 according to this embodiment, a plurality of rollers 15 and 16 arranged in the circumferential direction are arranged in two rows. These two rows of rollers 15 and 16 are rotatably held by a common holder 7. In the cage 7, a plurality of pockets 7b and 7c are arranged at equal intervals in the circumferential direction and formed in two rows in the axial direction, and one roller 15 and 16 is accommodated in each pocket 7b and 7c. The rollers 15 and 16 are held so as to be movable in the radial direction in the pockets 7b and 7c. The cage 7 is not fixed to the casing 8 and is provided to be rotatable in the circumferential direction.

  Further, in the speed reducer 1 according to the present embodiment, a fixed shaft 17 fixed so as not to rotate with respect to the casing 8 is disposed coaxially with the output shaft 2 on the inner diameter side of the eccentric member 3. A plurality of teeth 17a are provided at equal intervals in the circumferential direction on the outer peripheral surface of the fixed shaft 17, and a curved tooth groove 17b (see FIG. 8) is formed between the teeth 17a. The number of teeth of the fixed shaft 17 is set to a number different from the number of teeth of the output shaft 2. Of the two rows of rollers 15, 16, one row of rollers 15 (hereinafter referred to as “first roller”) is between the teeth 17 a or tooth grooves 17 b of the fixed shaft 17 and the inner peripheral surface of the cylindrical member 5. The other row of rollers 16 (hereinafter referred to as “second rollers”) is disposed between the teeth 2 a or tooth grooves 2 b of the output shaft 2 and the inner peripheral surface of the cylindrical member 5. The first roller 15 and the second roller 16 are configured to roll on the inner peripheral surface of the cylindrical member 5.

  Similarly to the above embodiment, also in this embodiment, the cylindrical member 5 is arranged on the inner peripheral surface of the eccentric member 3 via the needle roller bearing 4. For this reason, the inner peripheral surface of the cylindrical member 5 is arranged eccentrically with respect to the center axis of the output shaft 2 and the fixed shaft 17. Therefore, as shown in FIGS. 8 and 9, the centers Q1 and Q2 of the circles passing through the central axes of the first roller 15 and the second roller 16 aligned on the inner peripheral surface of the cylindrical member 5 are also the central axes of the fixed shaft 17. The distance Y is eccentric in the radial direction with respect to O1 or the central axis O2 of the output shaft 2. For this reason, the first roller 15 and the second roller 16 are fixed to the fixed shaft 17 or the tooth groove 17b of the output shaft 2 in a part of the circumferential direction on the inner peripheral surface of the cylindrical member 5 (the lower side of FIGS. 8 and 9). , 2b are arranged close to and engaged with each other (position entering the tooth gap), and at a position opposite to this (on the upper side in FIGS. 8 and 9), the fixed shaft 17 or the output shaft 2 It arrange | positions in the position which spaces apart and does not engage with the tooth spaces 17b and 2b.

The number of the rollers 15 and 16 is appropriately determined according to the reduction ratio of the opposing shaft (the output shaft 2 or the fixed shaft 17). Specifically, if the reduction ratio of the fixed shaft 17 is i1 and the reduction ratio of the output shaft 2 is i2, the number of teeth 2a and 17a is one more than the reduction ratio of the corresponding shaft (i1 + 1),
It is set to (i2 + 1), or one less number (i1-1), (i2-1). The number of rollers 15 and 16 is set to a divisor of the reduction ratios i1 and i2.

  Then, operation | movement of the reduction gear which concerns on this embodiment is demonstrated.

  When the driving force is input from the outside and the eccentric member 3 rotates, the first roller 15 and the second roller 16 reciprocate in the radial direction with respect to the output shaft 2 and the fixed shaft 17 accordingly. At this time, the first roller 15 rotates along the tooth groove 17b of the fixed shaft 17 and moves to the adjacent tooth groove 17b. Move in the circumferential direction by one tooth. As a result, the cage 7 rotates at a reduced speed relative to the eccentric member 3.

  When the cage 7 rotates, the second roller 16 held by the cage 7 also rotates. At the same time, the second roller 16 also reciprocates in the radial direction as the eccentric member 3 rotates, so that the second roller 16 rotates along the tooth groove 2b of the output shaft 2 to the adjacent tooth groove 2b. Moving. At this time, when the second roller 16 presses the wall of the tooth gap 2b, the output shaft 2 rotates by receiving a circumferential force. Thereby, every time the eccentric member 3 rotates, the output shaft 2 rotates by one tooth, decelerates and rotates with respect to the eccentric member 3. Further, since the output shaft 2 rotates with the rotation of the cage 7, the output shaft 2 rotates by the number of rotations of the cage 7 in addition to the decelerated rotation accompanying the rotation of the eccentric member 3. For this reason, the rotation speed of the output shaft 2 is an absolute value of the difference between the rotation speed of the decelerating rotation accompanying the rotation of the eccentric member 3 and the rotation speed of the cage 7.

That is, assuming that the reduction ratio of the fixed shaft 17 is i1 and the reduction ratio of the output shaft 2 is i2, the reduction ratio by the reduction gear according to the present embodiment is obtained by the following equation 1.

  Reduction ratio = i1 × i2 / | i1-i2 |

For example, when the reduction ratio (i1) of the fixed shaft 17 is 60 and the reduction ratio (i2) of the output shaft 2 is 63, the reduction ratio is 1260 from Equation 1 above.

  As described above, the speed reducer according to the present embodiment includes the output shaft 2, the fixed shaft 17, and the two rows of rollers 15 and 16 facing the tooth surfaces. , 16 is configured to transmit the rotation while decelerating between the motors 16 and 16, so that a high torque can be obtained with a large reduction ratio.

  Moreover, also in the reduction gear 1 which concerns on this embodiment, it is possible to arrange | position a reduction gear in a hollow motor similarly to the reduction gear which concerns on the said embodiment. FIG. 10 shows an electric actuator in which the speed reducer according to this embodiment is mounted in an electric motor. FIG. 11 is an exploded perspective view of the electric actuator shown in FIG.

  The electric actuator 9 according to the present embodiment is the same as that of the electric actuator 9 according to the above-described embodiment, except that the electric actuator (a type including one row of rollers) is changed to a speed reducer including two rows of rollers. This is the same as the electric actuator according to the embodiment. Therefore, when the electric motor 11 is driven and the rotor 13 rotates, the eccentric member 3 rotates integrally with the rotor 13, and the output shaft 2 decelerates relative to the eccentric member 3 by the operation of the speed reducer 1 described above. Rotate.

  Thus, even in a reduction gear including two rows of rollers, the eccentric member 3 that is a member to which driving force is input is arranged on the outer diameter side, so that it becomes easier to input driving force from the outer diameter side. It becomes easy to arrange the speed reducer on the inner diameter side of a hollow motor, a hollow shaft or the like. As a result, the speed reducer does not have to be arranged in series in the axial direction with respect to the drive source, so that the axial dimension of the speed reducer and the drive source can be reduced, and mountability is improved. Particularly, a speed reducer including two rows of rollers is suitable for a device that requires a high output with a high speed reduction ratio because it can obtain a high torque while being small.

  The embodiment of the speed reducer according to the present invention has been described above. However, the present invention is not limited to the above embodiment, and can be implemented in various forms without departing from the gist of the present invention. Of course.

DESCRIPTION OF SYMBOLS 1 Reducer 2 Output shaft 2a Tooth 3 Eccentric member 3a Engagement part 6 Roller 7 Cage 11 Electric motor 12 Stator 13 Rotor 13a Engagement part 15 Roller (1st roller)
16 rollers (second roller)
17 Fixed shaft 17a Teeth

Claims (3)

An output shaft having a plurality of teeth on the outer peripheral surface;
An eccentric member disposed on the outer diameter side of the output shaft and having an inner peripheral surface that is eccentric with respect to the output shaft;
A plurality of rollers disposed between the output shaft and the eccentric member;
A holder for rotatably holding the roller;
Each time the eccentric member makes one rotation, the roller pushes the tooth groove of the output shaft to rotate the output shaft by one tooth in the circumferential direction, so that the output shaft decelerates relative to the eccentric member. A speed reducer that rotates. A plurality of teeth are provided on the outer peripheral surface, and are arranged coaxially with the output shaft on the inner diameter side of the eccentric member and fixed so as not to rotate,
A plurality of rollers disposed between the fixed shaft and the eccentric member;
The cage is configured to rotatably hold the roller disposed between the fixed shaft and the eccentric member and the roller disposed between the output shaft and the eccentric member. And
Each time the eccentric member makes one rotation, the roller disposed between the fixed shaft and the eccentric member moves in the circumferential direction by one tooth with respect to the fixed shaft, and the output shaft and the eccentric member. The roller disposed between the member pushes the tooth groove of the output shaft and rotates the output shaft in the circumferential direction by one tooth, whereby the output shaft rotates at a reduced speed with respect to the eccentric member. The speed reducer according to claim 1.   The speed reducer according to claim 1 or 2, wherein an engaging portion that engages with an inner peripheral surface of the rotation driving portion is provided on an outer peripheral surface of the eccentric member.

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