WO2023188071A1

WO2023188071A1 - Speed reducer

Info

Publication number: WO2023188071A1
Application number: PCT/JP2022/015856
Authority: WO
Inventors: 良一吉野; 美千広亀田; 貴俊木森; 大樹佐藤
Original assignee: 株式会社Nittan
Priority date: 2022-03-30
Filing date: 2022-03-30
Publication date: 2023-10-05

Abstract

Provided is a speed reducer constructed in a well-balanced, compact size. A speed reducer (W1) comprises: an input shaft (1) with an eccentric part (1a); an output shaft (10) having a flange part (10a), and a circular hole (10b) formed in the flange part (10a), on a circumferential orbit centered on a rotation axis; a fixed inner trochoid plate (7) having a through-hole (7a), and a wavy curved surface formed on an inner circumferential side surface (7b) of the through-hole; a pin (6) held between the inner circumferential side surface (7b) of the inner trochoid plate (7) and an outer circumferential side surface of the eccentric part (1a); and a holding member (8) that holds the pin (6) while restricting rotation of the pin (6). One end of the pin (6) is rotatably received in the circular hole (10b) while being at least partially abutted on the inner circumferential side surface of the circular hole (10b). The rotation of the input shaft (1) causes a rotational motion of the pin (6) around the eccentric part (1a), and the rotational motion of the pin causes the output shaft (10) to rotate.

Description

Decelerator

The present invention relates to a speed reducer that reduces the rotational speed input to an input shaft and outputs it from an output shaft.

Conventionally, a cycloid reducer has been disclosed that is interposed between an electric motor and a wheel hub to reduce the rotational speed of the motor and transmit it to the wheel hub bearing (for example, Patent Document 1 and Patent Document 2). .

Patent No. 5010484 WO2021/024312

However, in the reducer of Patent Document 1, the outer pin, the curved plate, and the output pin inserted through the hole formed in the curved plate are essential components, and there was a problem that the size in the radial direction became large. . On the other hand, in the reducer of Patent Document 2, the size in the radial direction is reduced by arranging the outer pin in the axial direction as a crankshaft, but the structure in which the outer pin is arranged in the axial direction tends to increase the length in the axial direction. For this reason, there is a need for a reduction gear that is well-balanced and compact in size.

The present invention has been made in view of this, and provides a reduction gear that is well-balanced and has a reduced size.

In order to solve the above problem, the reducer of the present disclosure has an input shaft provided with an eccentric part and a flange part, and the flange part has a circular hole on a circumferential orbit centered on the rotation axis. an output shaft formed with an inner trochoid plate; A pin held between an inner circumferential side surface and an outer circumferential side surface of the eccentric portion, and a holding member that restricts rotation of the pin and holds the pin, and one end of the pin is at least partially inserted into the round hole. The input shaft is rotatably received in the round hole while being in contact with the inner circumferential side surface, and the rotation of the input shaft causes the pin, which is held between the eccentric part and the inner trochoid plate, to be rotated in the eccentric direction. The pin rotates around the core, and the pin rotates while at least partially abutting it within the round hole, so that the rotational movement of the pin is centered around the rotational axis of the output shaft. The output shaft is configured to be converted into a rotational motion to rotate the output shaft.

According to this aspect, the pin serves both as an output pin and an input pin. It does not have the external pins used in conventional cycloid reducers, allowing for a smaller external size. The number of parts is reduced, and the overall size can be reduced.

According to another aspect, the input shaft and the output shaft are rotatably held in a housing with their rotation axes aligned with each other, and the inner trochoid plate is fixed to the housing. It was configured as follows. According to this aspect, the loaded endotrochoid is completely fixed to the housing. Although the size is small, the rigidity can be increased.

The holding member was configured in the shape of a flat ring, and a hole was provided on a circumferential orbit centered on the ring center axis, and the pin was press-fitted into the hole. According to this aspect, by press-fitting and connecting the pin with the holding member, rotation is restricted and only revolution is permitted. The flat plate-shaped holding member performs the function of regulating rotation, and can be kept compact without being elongated in the axial direction.

According to another aspect, an eccentric part collar rotatably supported by the eccentric part is attached to the eccentric part, and a first pin collar is attached to the pin. The pin is held between the inner circumferential side surface of the inner trochoid plate and the outer circumferential side surface of the eccentric section via the eccentric collar and the first pin collar, and the pin is held in the round hole. A second pin collar is interposed between the pin and the pin. According to this aspect, the surfaces come into smooth contact with each other, reducing friction and increasing rigidity.

In one aspect, n pins are provided around the axis of the eccentric portion, and the inner trochoid plate has a leaf shape in which n+1 or more trochoids are offset. According to this aspect, the reduction ratio can be set by the number n.

Further, in one aspect, a first counterweight formed so that the center of gravity is at an eccentric position is attached to the input shaft at a position different from the pin in the axial direction, and the first counterweight is The input shaft is configured such that the eccentric direction of the center of gravity is 180 degrees out of phase with the protruding direction of the eccentric portion of the input shaft.

Further, in one aspect, the eccentric part is a first eccentric part, and the input shaft has a second eccentric part having a phase different from the first eccentric part by 180 degrees, and A second counterweight was attached to the core. The counterweight allows the input shaft to rotate in a well-balanced manner while maintaining high pin rigidity, improving the performance of the reducer.

As is clear from the above description, it is possible to provide a reduction gear that is well-balanced and size-saving.

1 is a sectional view of a speed reducer according to an embodiment of the present invention. It is an exploded perspective view of the same reduction gear. Bearings are omitted. 2 is a cross-sectional view taken along line AA in FIG. 1. FIG. 2 is a sectional view taken along line BB in FIG. 1. FIG. It is a sectional view of a reduction gear concerning a modification. FIG. 7 is an exploded perspective view of a reduction gear according to a modification. Bearings are omitted. 6 is a sectional view taken along line CC in FIG. 5. FIG. 6 is a sectional view taken along line DD in FIG. 5. FIG.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. The embodiments are illustrative rather than limiting the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention. In addition, in the following description of the embodiment and modified examples, the same configurations are denoted by the same reference numerals, and overlapping description will be omitted as appropriate.

(First embodiment)
FIG. 1 is a sectional view of a speed reducer W1 according to the first embodiment. FIG. 2 is an exploded perspective view of the speed reducer W1. In FIG. 2, bearings are omitted.

The speed reducer W1 is mounted on the wheel drive section of the vehicle, and is interposed between the motor M and the wheel hub H. The speed reducer W1 has an input shaft 1 as an input shaft and an output shaft 10 as an output shaft, and the rotation of the input shaft 1 is decelerated and output from the output shaft 10.

The input shaft 1 is fitted into a motor M, and as the motor M rotates, the input shaft 1 rotates. The output shaft 10 is connected to a wheel hub H to which wheels (not shown) are connected, and the rotation of the output shaft 10 is transmitted to the wheels through the wheel hub H. The rotation of the motor M is decelerated by a speed reducer W1 and transmitted to the wheels, so that the wheels rotate. Either a configuration in which the input shaft 1 is directly driven as a rotating shaft on the motor M side, or a configuration in which the input shaft 1 is connected to and driven by the rotating shaft of the motor M may be used.

As shown in FIG. 2, the reducer W1 includes an input shaft 1, a first counterweight 2, a connecting member 3, a first pin collar 4, an eccentric collar 5, a pin 6, an inner trochoid plate 7, a holding member 8, It includes a second counterweight 9, an output shaft 10, a housing body 11, a housing cover 12, and a second pin collar 13.

The housing body 11 and the housing cover 12 are housing parts for holding and protecting the components of the reducer W1, and are formed into a hollow, substantially cylindrical shape with both upper and lower ends open. One of the openings of the housing body 11 and the housing cover 12 has a reduced diameter, and the other opening has flanges 11a and 12a formed as joints. The housing main body 11 and the housing cover 12 have a box shape with flanges 11a and 12a facing each other. Each component is held in the inner space of the housing body 11 and the housing cover 12 thus formed. A portion of the input shaft 1 is inserted through the diameter-reduced opening of the housing cover 12 and held therein. Further, a portion of the output shaft 10 is inserted through and held in the diameter-reduced opening of the housing body 11.

The input shaft 1 is formed into a substantially cylindrical rod shape, and is housed inside a housing body 11 and a housing cover 12, which are housings. One end (lower side in FIG. 1) of the input shaft 1 protrudes from the diameter-reduced opening of the housing cover 12, and is inserted into and fixed to the motor M.

The input shaft 1 has a first eccentric portion 1a that is eccentric with respect to the rotation axis of the input shaft 1 in a portion housed in the housing.

The input shaft 1 also has a second eccentric part 1b arranged at a phase 180 degrees different from the first eccentric part 1a. A first counterweight 2 is press-fitted into the input shaft 1 at a portion other than the first eccentric portion 1a and the second eccentric portion 1b. Further, a second counterweight 9 is attached to the second eccentric portion 1b via a bearing BR4. The first counterweight 2 and the second counterweight 9 serve as weights to balance the rotating input shaft 1.

The first counterweight 2 has an approximately disk-shaped but asymmetrical outer shape, and is formed so that its center of gravity is not at the center of the approximately disk shape but at an eccentric position, so that the load is tilted in one direction. It is configured. The direction in which this load is applied is 180 degrees different from the protruding direction of the first eccentric portion 1a, and the first eccentric portion 1a is mounted on the input shaft 1 without using a bearing. As a result, the first counterweight 2 maintains a balance between the first eccentric portion 1a, the connecting member 3, the first pin collar 4, the eccentric portion collar 5, the pin 6, and a portion of the second pin collar 13. I'm taking it.

The first counterweight 2 is attached to the input shaft 1 in a different arrangement in the axial direction from the pin 6 described later.

The disk-shaped second counterweight 9 is provided with an insertion hole 9a for the pin 6 to be inserted on the center circumferential orbit. The pin 6 is inserted into the insertion hole 9a, but the inner diameter is made large so that the inserted pin 6 and the insertion hole 9a do not come into contact with each other. The second counterweight 9 and the pin 6 inserted into the insertion hole 9a do not come into contact with each other even if they rotate. In this way, the first counterweight 2 and the second counterweight 9 are configured to function without interfering with the movement of the pin 6.

The inner trochoid plate 7 has an approximately disk-shaped outer shape, and a large through hole 7a is formed in the center. A wavy curve is formed on the inner peripheral side surface 7b of the through hole 7a. The inner trochoid plate 7 has its outer edge sandwiched between flanges 11a and 12a formed at the joint openings of the housing body 11 and the housing cover 12, and is fastened to the housing body 11 and the housing cover 12 by a fixing member (not shown). be done. As a result, the inner trochoid plate 7 is fixed to the housing body 11 and the housing cover 12, and will not rotate or move due to pressing force or frictional force even if it interferes with other parts.

The eccentric portion collar 5 has a short cylindrical shape and is rotatably supported by the first eccentric portion 1a of the input shaft 1 via a bearing BR2. The collar is a cylindrical member in which a cylindrical hole is formed, and is a part that is inserted into the mounted member to smooth the rotation of the mounted member. In this embodiment, collars are mainly arranged at locations where rigidity is required and where shear loads are applied, and the collars can be replaced with bearings as appropriate.

The eccentric collar 5 is arranged within the through hole 7a of the inner trochoid plate 7. The eccentric portion collar 5 receives an eccentric input from the input shaft 1.

The pin 6 is formed into a cylindrical rod shape, and is a component that is driven by the input shaft 1 and outputs driving force to the output shaft 10. That is, pin 6 serves as both an input pin and an output pin. The outer pin and inner pin, which were essential in the cycloid reducer of the prior art, can now be provided with only the pin 6, and the reducer W1 has a more compact external shape than the cycloid reducer of the prior art.

A cylindrical first pin collar 4 is inserted into the pin 6. The pin 6 is held between the eccentric collar 5 and the inner trochoid plate 7 at the location where the first pin collar 4 is inserted. Specifically, it is held between the inner circumferential side surface 7b of the inner trochoid plate 7 and the outer circumferential side surface of the first eccentric section 1a via the first pin collar 4 and the eccentric section collar 5. In this embodiment, in order to reduce friction, the first eccentric part 1a is fitted with an eccentric part collar 5, and the pin 6 is fitted with a first pin collar 4. The pin 6 may be directly sandwiched between the inner circumferential side surface 7b of the inner trochoid plate 7 and the outer circumferential side surface of the first eccentric section 1a without using the first pin collar 4 and the eccentric section collar 5. . The pins 6 are arranged at equal intervals on the same circumference.

The wavy curved surface of the inner trochoid plate 7 of the reducer W1 is designed, for example, as follows. In an inner trochoidal curve formed by a moving circle rolling inside a fixed circle, when there are n pins 6 rolling on the inner trochoidal curve, the shape of the rolling surface of the pin is defined as an inner trochoidal curve of n+1 leaves.

In this embodiment, seven pins 6 are used, and eight corrugations (trochoid offset leaf shapes) are provided on the inner circumferential side surface 7b of the inner trochoid plate 7. Based on the trochoidal curve, a portion of the outer peripheral surface of the pin is appropriately offset so that it is always in contact with the pin.

When the eccentric collar 5 is placed at a predetermined position of the through hole 7a of the inner trochoid plate 7, a first pin collar is placed between the inner circumferential side surface 7b of the inner trochoid plate 7 and the outer circumferential side surface of the eccentric collar 5. A gap is formed with a size that allows the pin 6 with the pin 4 attached thereto to be inserted therein. By inserting a plurality of pins 6 into this gap, the plurality of pins 6 are sandwiched between the inner circumferential side surface 7b of the inner trochoid plate 7 and the outer circumferential side surface of the first eccentric portion 1a.

The holding member 8 is a ring-shaped flat plate member with a central hole 8a formed in the center. Furthermore, in addition to the central hole 8a, the holding member 8 has a through hole 8b formed on a circumferential orbit around the central axis of the central hole 8a. The through holes 8b are provided around the central hole 8a of the holding member 8 at equal intervals in the circumferential direction by the number of pins 6 (seven in this embodiment), and each pin 6 is press-fitted into the through hole 8b. Ru. The holding member 8 holds the pin 6 and is rotatably supported by the first eccentric portion 1a via a bearing BR3 mounted in the central hole 8a.

The connecting member 3 has the same structure as the holding member 8, and is a ring-shaped flat plate member in which a central insertion hole 3a is formed as an insertion hole in the center. Similar to the holding member 8, the through hole 3b is formed on a circumferential orbit centered on the central axis of the ring-shaped connecting member 3. The through holes 3b are provided around the central insertion hole 3a of the connecting member 3 at equal intervals in the circumferential direction by the number of pins, and the pins 6 are press-fitted into the through holes 3b. The arrangement of the through holes 3b in the connecting member 3 is configured to be equal to the arrangement of the through holes 8b of the holding member 8. Therefore, the pin 6 press-fitted into the connecting member 3 and the holding member 8 are held parallel to each other.

The connecting member 3 and the holding member 8 connect the pin 6 by press-fitting, thereby preventing the pin 6 from rotating in response to eccentric input from the input shaft 1, and preventing rotation (mainly revolution) around the input shaft 1. operation). The connecting member 3 and the holding member 8 both have the role of connecting the pin 6 and regulating the rotation of the pin 6, and have the same structure. They can be substituted for each other, and there is no problem even if only one of them is used.

The central insertion hole 3a of the connecting member 3 is an insertion hole for the input shaft 1, and the connecting member 3 is arranged in the first eccentric portion 1a with the input shaft 1 inserted through the central insertion hole 3a. The center insertion hole 3a is formed with an inner diameter larger than the outer diameter of the first eccentric portion 1a, and even if the input shaft 1 is inserted into the center insertion hole 3a, the connecting member 3 does not allow the first eccentric portion 1a to pass through the center insertion hole 3a. The structure is such that it does not come into contact with the included input shaft 1.

The connecting member 3 and the holding member 8 are arranged on the first eccentric portion 1a of the input shaft 1 so as to sandwich the eccentric portion collar 5 and the inner trochoid plate 7 in the axial direction. The holding member 8 is rotatably supported by the first eccentric part 1a via a bearing, but the connecting member 3 is not held by the first eccentric part 1a, but is held by connecting a cylindrical pin 6. This serves to assist the holding member 8. The pin 6 is supported at two locations in the axial direction by the holding member 8 and the connecting member 3, and is stably arranged. Similarly to the holding member 8, a bearing may be installed in the central insertion hole 3a of the connecting member 3 so that the connecting member 3 is rotatably supported by the first eccentric portion 1a of the input shaft 1.

The output shaft 10 has a solid flange shape having a substantially cylindrical rod-shaped shaft portion 10c and a flange portion 10a formed at one end of the shaft portion 10c. The output shaft 10 is arranged with the flange portion 10a facing the input shaft 1 side, and the other end of the input shaft 1 (the upper side in FIG. 1) is inserted into the engagement hole provided at the center of the bottom surface of the flange portion 10a. It is linked via BR5. As a result, the input shaft 1 and the output shaft 10 are connected so that their rotation axes coincide with each other and can rotate relative to each other. Hereinafter, the rotation axes of both shafts will be referred to as the central axis x.

The input shaft 1 and the output shaft 10 are housed in a housing body 11 and a housing cover 12 with one end protruding from an opening, and are inserted into the housing body 11 and the housing cover 12 through bearings BR1 and BR6, respectively. It is held rotatably. An end of the shaft portion 10c of the output shaft 10 protrudes from the housing body 11 and is connected to the wheel hub H. The outer peripheral surface of the shaft portion 10c is fixed to the wheel hub H, and the rotation of the output shaft 10 is transmitted to rotate the wheel hub H.

In the flange portion 10a of the output shaft 10, round holes 10b are provided as many as the number of pins at equal intervals in the circumferential direction on a circumferential orbit centered on the central axis x. One end (the upper end in FIG. 1) of the pin 6 is received in the round hole 10b so as to be eccentrically rotatable.

A cylindrical second pin collar 13 having the same structure as the first pin collar 4 is inserted into the upper end of the pin 6, and the pin 6 has an upper end through which the second pin collar 13 is inserted. It is received in the round hole 10b so as to be eccentrically rotatable. The round hole 10b is formed so that at least a part of the outer circumferential side of any one of the pins 6 is always in contact with the round hole 10b, and at least a part of the outer circumferential side of the pin 6 is inserted into the round hole 10b through the second pin collar 13. The outer circumferential side of the second pin collar 13 is configured to rotate and push the inner circumferential side of the round hole 10b. Thereby, the revolution rotation of the pin 6 is converted into a movement that rotates the output shaft 10 around the central axis x.

The round hole 10b is formed so that its diameter is larger than the outer diameter of the pin 6 through which the second pin collar 13 is inserted. The second pin collar 13 is arranged such that the pin 6 is inserted thereinto to enable rotation relative to each other, and at least a part of the outer circumferential side surface of the second pin collar 13 is in contact with the round hole 10b. Ru. The rotation of the pin 6 is transmitted to the output shaft 10 via the second pin collar, causing the output shaft 10 to rotate around the central axis x.

(Movement of reducer W1)
The operation of the reduction gear W1 will be explained. FIG. 3 is a cross-sectional view taken along line AA in FIG. It is an explanatory diagram mainly showing the movement of the input shaft 1 and the pin 6. FIG. 4 is a cross-sectional view taken along line BB in FIG. 2 is an explanatory diagram mainly showing the movement of the output shaft 10 and the pin 6. FIG.

First, the movement of the input shaft 1 and pin 6 will be explained using FIG. 3. When the motor M is driven and the input shaft 1 rotates around the central axis x, the eccentric portion collar 5 supported by the first eccentric portion 1a via the bearing BR2 receives eccentric input from the input shaft 1. The input shaft 1 rotates around the central axis x in a direction opposite to the rotation direction of the input shaft 1, and also revolves in the same direction as the input shaft 1 rotation direction.

When the input shaft 1 rotates, the shift of the center of gravity of the input shaft 1, which has the first eccentric part 1a and the second eccentric part 1b, is kept within the allowable range due to the eccentric load of the first counterweight 2, which is a balancer, and the input shaft 1 is rotated. The shaft 1 rotates stably. Furthermore, the second counterweight 9 rotatably supported by the second eccentric part 1b rotates so that the phase is 180 degrees different from that of the first eccentric part 1a, thereby achieving balance.

The pin 6 is held between the first eccentric part 1a and the inner peripheral side surface 7b of the inner trochoid plate 7 within the through hole 7a of the inner trochoid plate 7 via the eccentric collar 5 and the first pin collar 4. ing. The inner trochoid plate 7 is completely fixed to the housing body 11 and the housing cover 12, and does not rotate or move. The pin 6 is press-fitted and connected to the connecting member 3 and the holding member 8, and rotation of each pin 6 is restricted. Therefore, the pin 6 is driven by the eccentric collar 5 via the first pin collar 4, revolves around the first eccentric part 1a, and moves along the inner circumferential side surface 7b of the inner trochoid plate 7. Moving.

Here, the waveform curved surface of the inner circumferential side surface 7b is formed so that the number of trochoidal offset leaves (n+1 pieces) is greater than the number of pins (n pieces). The fact that the trochoidal offset leaf shape is formed with the number of leaves n+1 means that the number of pins is n+1 and the first eccentric portion 1a is configured to go around once, but in reality there are only n pins. Therefore, the rotation of the pin is relatively delayed by 1/(n+1) rotation. The delay is reduced by that amount and the rotation is made in the opposite direction. That is, when the input shaft 1 rotates once, the first eccentric portion 1a rotates once in the same rotation direction as the input shaft 1, and the pin 6 rotates 1/8 in the opposite direction to the rotation direction of the input shaft 1. It revolves only around the circumference. The rotation of the input shaft 1 is reduced to 1/8 of the rotation speed of the input shaft 1, causing the pin 6 to revolve.

Next, the relationship between the pin 6 and the output shaft 10 will be shown using FIG.

The pin 6 is inserted into the round hole 10b of the output shaft 10, and the second pin collar 13 is arranged so as to come into contact with the inner surface of the round hole 10b. The pin 6 moves along the inner surface of the round hole 10b via the second pin collar 13, and rotates at a reduced speed in a direction opposite to the rotational direction of the input shaft 1. The rotation of the pin 6 is restricted, and movement relative to the round hole 10b is accepted by the second pin collar 13 as rotation along the inner surface of the round hole 10b. The decelerated revolution of the pin 6 pushes the inner surface of the round hole 10b and rotates the output shaft 10 around the central axis x.

With the above configuration, the rotation of the input shaft 1 is transmitted to the output shaft 10 as rotation in the opposite direction at a rotation speed of 1/(n+1). The speed reducer W1 rotates the wheels connected to the wheel hub H at a speed where the speed of the motor M is reduced to 1/(n+1). The wheels will rotate in the opposite direction to the rotation direction of the motor M.

(effect)
The speed reducer W1 is different from conventional speed reducers in that it does not have any outer pins. Accordingly, the external size can be reduced. In addition, the rotation of the pin 6 is restricted, and its eccentric movement and revolution are absorbed by the round hole formed in the flange portion 10a of the output shaft 10, and only the revolution of the pin 6 is restricted to the output shaft 10. is transmitted, causing the output shaft 10 to rotate. Since the reduction ratio of the reduction gear W1 is determined by the number of corrugations of the inner trochoid plate 7 (the number of trochoid offset leaf shapes) and the number of pins 6, the outer diameter is difficult to increase even if the reduction ratio is increased. Pin 6 serves as both an output pin and an input pin, and since both pins can be integrated, the number of parts can be reduced and the size can be reduced. In this way, the reduction gear W1 has a well-balanced overall structure with a reduced size.

In addition, since the inner trochoid plate 7, which is subject to a large load, is fixed to the housing, the rigidity can be increased. In addition, a collar is used to ensure smooth rotation of the pin and is resistant to radial loads. A trochoidal curve is used, and by making contact with the outer surface of the pin 6, smooth rotation can be achieved without producing any collision noise. In this way, the speed reducer W1 has increased rigidity.

(Modified example)
The configuration of the present disclosure is not limited to the form of the reduction gear W1 described above.

The second pin collar 13 is not limited to a cylindrical shape, and for example, an eccentric collar in which the central axis of the outer circumferential side surface and the central axis of the inner circumferential side surface are offset may be used.

Assuming that the second pin collar of the eccentric collar is a second pin collar 13A, the second pin collar 13A has a cylindrical outer shape and has a through hole whose central axis is offset from the central axis of the cylindrical shape. The outer diameter of the cylindrical shape is approximately slightly smaller than the outer diameter of the round hole 10b. The diameter of the through hole is slightly larger than that of the pin 6. The second pin collar 13A is arranged in the round hole 10b with the pin 6 inserted into the through hole. At this time, the offset of the central axis of the eccentric shape described above is configured to accept eccentric rotation of the first eccentric portion 1a. The round hole 10b, the second pin collar 13A of the eccentric collar, and the pin 6 are supported so that they can rotate relative to each other, and when the pin 6 rotates around the first eccentric portion 1a, the outer circumferential side of the second pin collar 13A rotates. , while rotating around the center axis of the pin 6, pushes the inner circumferential side of the round hole 10b, thereby causing the output shaft 10 to rotate around the center axis x.

(Modification 2)
A reduction gear W2, which is a modification of the present invention, will be explained using FIGS. 5 to 8. FIG. 5 is a sectional view of the speed reducer W2. FIG. 6 is an exploded perspective view of the reducer W2. In FIG. 6, bearings are omitted.

As shown in FIGS. 5 and 6, the reducer W2 includes an input shaft 1', a connecting member 3, a first pin collar 4, an eccentric collar 5, a pin 6, an inner trochoid plate 7, an output shaft 10, and a housing body. 11, it has a housing cover 12.

The reducer W2 is not equipped with the first counterweight 2 and the second counterweight 9, but instead has another pair of first pin collars 4', eccentric collars 5', pins 6', and inner trochoids. A plate 7' is provided. These are collectively referred to as a counterweight unit CU. Further, the first pin collar 4, the eccentric collar 5, the pin 6, and the inner trochoid plate 7, which are the original, are collectively referred to as an original unit OU.

The input shaft 1' is the same as the input shaft 1 except that it has a first eccentric part 1a, does not have a second eccentric part 1b, and has another first eccentric part 1a' instead. The structure is as follows. The first eccentric part 1a' has an eccentric direction 180 degrees different from that of the first eccentric part 1a, and in the axial direction, the output shaft 10 is arranged with respect to the first eccentric part 1a. It is provided in the opposite direction (downward in FIG. 5).

The counterweight unit CU is 180 degrees out of phase with the paired original unit OU, that is, rotated 180 degrees, and is arranged at the first eccentric portion 1a' in the axial direction.

The connecting member 3 is arranged between the original unit OU and the counterweight unit CU. Both the pin 6' and the pin 6 are press-fitted into the hole formed in the connecting member 3 and are connected. At this time, the pin 6 protrudes in the direction in which the output shaft 10 is arranged and is press-fitted, and the pin 6' protrudes in the opposite direction to the pin 6 and is press-fitted, thereby connecting them. In this embodiment, the pin 6 is press-fitted into the upper surface of the connecting member 3 and protrudes upward, and the pin 6' is press-fitted into the bottom surface of the connecting member 3 and protrudes downward, so that the pin 6, the pin 6', and the connecting member 3 are integrally connected.

In this embodiment, the holding member 8 is not used, and the connecting member 3 performs the function of the holding member 8, connects the pin 6, regulates rotation, and holds it. The connecting member 3 has the same structure as the holding member 8, and it can be said that the connecting member 3 of this embodiment is the holding member 8. In place of the connecting member 3, a holding member 8 and another pair of holding members 8' may be used.

The outer edges of the inner trochoid plate 7 and the inner trochoid plate 7' are sandwiched between the flange portion 11a of the housing body 11 and the flange portion 12a of the housing cover 12 with a spacer 20 in between, so that the housing body 11 and the housing cover 12 It is fastened with a fixing member (not shown). Thereby, the inner trochoid plate 7 and the inner trochoid plate 7' are fixed to the housing body 11 and the housing cover 12, which are the housings.

The spacer 20 is arranged to ensure a space for the connecting member 3 arranged between the original unit OU and the counterweight unit CU. The spacer 20 is configured in the shape of a flat ring, and the inner diameter of the through hole formed in the center is configured to be large so as not to interfere with the holding member 8.

The movement of the reducer W2 will be explained. FIG. 7 is a sectional view taken along line CC in FIG. Mainly shows the original unit OU. FIG. 8 is a cross-sectional view taken along line DD in FIG. Mainly shows the counterweight unit CU.

As shown in FIGS. 7 and 8, the original unit OU and the counterweight unit CU are arranged with a phase difference of 180 degrees.

When the input shaft 1' rotates around the central axis x, the eccentric collar 5 held by the first eccentric part 1a via the bearing BR2 receives the eccentric input and rotates around the central axis x. It revolves around The pin 6 is driven by the eccentric collar 5 via the first pin collar 4, revolves around the first eccentric part 1a, and moves along the inner peripheral side surface 7b of the inner trochoid plate 7.

When the input shaft 1 rotates, the counterweight unit CU moves in the same way as the original unit OU, with a phase difference of 180 degrees. That is, when the input shaft 1' rotates around the central axis , revolves around the central axis x. The pin 6' is driven by the eccentric collar 5' via the first pin collar 4', revolves around the first eccentric part 1a', and rotates along the inner circumferential side surface 7b of the inner trochoid plate 7. and move.

By driving the counterweight unit CU in a phase opposite to that of the original unit OU, balance is maintained, the movement of the center of gravity of the input shaft 1' falls within an allowable range, and the input shaft 1 rotates stably.

The rotation of the pin 6 is received in the round hole 10b of the output shaft 10, and rotates the output shaft 10 around the central axis x. A cross-sectional view of the output shaft 10 of the speed reducer W2 is the same as FIG. 4. The output configuration of the speed reducer W2 is the same as that of the speed reducer W1, and a description thereof will be omitted.

The rotation of the pin 6' is not output to the output shaft 10 or other parts, but is simply driven as a counterweight for balance.

The counterweight unit CU uses the same parts as the original unit OU and operates as a well-balanced counterweight. Furthermore, since the same parts can be used for each unit, manufacturing costs can be reduced. Because the paired parts, the eccentric part collar 5 and the eccentric part collar 5', the pin 6 and the pin 6', and the first pin collar 4 and the first pin collar 4', move point-symmetrically about the central axis x. , the counterweight unit CU is a high-performance balancer in a reduction gear that makes complex movements, and improves the performance of the reduction gear W2.

The preferred embodiments of the present invention have been described above, but the above embodiments are only examples of the present invention, and these can be combined based on the knowledge of those skilled in the art, and such embodiments also fall within the scope of the present invention. include.

1: Input shaft 1a: First eccentric part (eccentric part)
1b: Second eccentric part 2: First counterweight 3: Connecting member 3b: Through hole 4: First pin collar 5: Eccentric part collar 6: Pin 7: Inner trochoid plate 7a: Through hole 7b: Inner peripheral side 8: Holding member 8b: Through hole 9: Second counterweight 10: Output shaft 10a: Flange portion 10b: Round hole 11: Housing body (housing)
12: Housing cover (housing)
13: Second pin collar W1: Reducer W2: Reducer x: Center shaft

Claims

an input shaft provided with an eccentric portion;
an output shaft having a flange portion, and a round hole formed in the flange portion on a circumferential orbit around the rotation axis;
an inner trochoid plate provided with a through hole, a wave-shaped curved surface formed on the inner peripheral side of the through hole, and fixed so as not to rotate;
a pin held between the inner circumferential side surface of the inner trochoid plate and the outer circumferential side surface of the eccentric portion;
a holding member that restricts rotation of the pin and holds it;
Equipped with
one end of the pin is rotatably received in the round hole with at least a portion of it abutting an inner circumferential side of the round hole;
The rotation of the input shaft causes the pin held between the eccentric part and the inner trochoid plate to rotate around the eccentric part,
The pin rotates in the round hole while at least partially in contact with the pin, so that the rotational movement of the pin is converted into rotational movement about the rotational axis of the output shaft, and the output rotate the axis,
A speed reducer characterized by:
The input shaft and the output shaft are rotatably held in a housing with their rotation axes aligned with each other,
the inner trochoid plate is fixed to the housing;
The reduction gear according to claim 1, characterized in that:
The holding member is configured in the shape of a flat ring, and a hole is provided on a circumferential orbit centered on the ring center axis, and the pin is press-fitted into the hole.
The reduction gear according to claim 1 or claim 2, characterized in that:
An eccentric part collar rotatably supported by the eccentric part is attached to the eccentric part, and a first pin collar is attached to the pin,
The pin is held between the inner circumferential side surface of the inner trochoid plate and the outer circumferential side surface of the eccentric portion via the eccentric portion collar and the first pin collar,
A second pin collar is interposed between the round hole and the pin,
The reduction gear according to any one of claims 1 to 3, characterized in that:
n pins are provided around the axis of the eccentric portion, and the inner trochoid plate has a leaf shape in which n+1 or more trochoids are offset.
The reduction gear according to any one of claims 1 to 4, characterized in that:
A first counterweight formed so that the center of gravity is at an eccentric position is attached to the input shaft at a position different from the pin in the axial direction,
The first counterweight is mounted such that the eccentric direction of the center of gravity is 180 degrees out of phase with the protruding direction of the eccentric portion of the input shaft.
The reduction gear according to any one of claims 1 to 5, characterized in that:
The eccentric part is a first eccentric part,
The input shaft has a second eccentric part having a phase different from the first eccentric part by 180 degrees,
A second counterweight is attached to the second eccentric part,
The reduction gear according to claim 6, characterized in that: