JP2007187290A - Reduction gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reduction gear having high power transmissibility though it is ultracompact. <P>SOLUTION: In this reduction gear provided with a sun gear 3 directly connected with a rotating shaft 2a of a motor 2, a plurality of planetary gears 4 engaged with the sun gear 3, and an internal gear 8 engaged with the planetary gears 4, and having a center coaxially with a rotating shaft of the sun gear 3, in a housing 1a connected with a motor case 2b, the planetary gears 4 are revolvably retained, the internal gear 8 is rotatably retained, an output shaft 8a formed on the internal gear 8 is rotatably retained by the housing 1a, and a power transmitting structure 11a is integrally formed on the output shaft 8a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reduction gear using a planetary gear mechanism.

  One actuator that converts rotational force into reciprocating power along the axial direction includes a reduction gear having a planetary gear mechanism built in a substantially cylindrical housing fixed to a motor case.

  In the actuator, a planetary gear mechanism as a speed reducer is provided on the output shaft of the motor, and the rotational motion of the motor is reduced to the linear motion (reciprocating motion) of the sliding member while being decelerated by the planetary gear mechanism. (See Patent Document 1).

  Here, as the planetary gear mechanism, a sun gear coaxially provided on the output shaft of a small motor, a rotating internal gear that is an output member screwed with the sliding member that is prevented from rotating, A fixed internal gear fixed to a motor, a plurality of planetary gears interposed between the sun gear, the rotary internal gear and the fixed internal gear so as to mesh with both, and each planetary gear. A mysterious planetary gear mechanism composed of a carrier that is rotatably held at equal intervals in the circumferential direction is suitable and widely used because a high reduction ratio can be obtained.

JP 2003-250246 A

  In a reduction gear using such a planetary gear, a screw is formed on the outer periphery of the rotating internal gear as an output member so as to be screwed with the sliding member. There has been a problem in that the sliding area is increased by sliding engagement with the rotating internal gear so that the sliding resistance increases and the power transmission efficiency decreases. Further, if the diameter of the sliding portion is increased, it is difficult to reduce the size of the entire apparatus.

  Accordingly, an object of the present invention is to provide a reduction gear that is ultra-compact and has a good power transmission rate.

  The first feature of the speed reducer of the present invention that achieves the above-described object is that a housing connected to a motor case of a motor has a sun gear directly connected to a rotating shaft of the motor, and a plurality of planets meshing with the sun gear. A reduction gear that meshes with a gear, a planetary gear, and has an internal gear that is coaxial with the rotation axis of the sun gear, the planetary gear being rotatably held, and the internal gear being rotatable And an output shaft formed on the internal gear is rotatably held on the housing, and a power transmission structure is integrally formed on the output shaft.

  A second feature of the speed reducer according to the present invention is that a housing connected to a motor case of a motor has a sun gear directly connected to a rotating shaft of the motor, a plurality of planetary gears meshed with the sun gear, and a planetary gear. And a reduction gear provided with an internal gear having a center coaxially with the rotation axis of the sun gear, wherein the internal gear is fixed to the housing, the planetary gear is rotatable and the sun gear is The output shaft formed on the carrier is rotatably held by the housing, and a power transmission structure is integrally formed on the distal end side of the output shaft. It is in.

  A third feature of the speed reducer according to the present invention is that the internal gear is formed by injection molding of a resin material.

  A fourth feature of the speed reducer according to the present invention is that the output shaft having the power transmission structure has a restricting member for restricting movement in a linear direction and is rotatably held in the housing. The fifth feature is that the power transmission mechanism of the output shaft has a feed screw structure or a cam structure for converting a rotational motion into a linear motion. A sixth feature is that a pressurizing member is provided that applies a pressure to a moving member that is disposed on the output shaft and is linearly movable in the axial direction.

  Further, a seventh feature of the speed reducer according to the present invention is that the moving member is an adjustment member that adjusts a fluid flow rate, and an eighth feature is that a direct movement of a plunger for sucking and discharging liquid or gas. It is used as a moving mechanism.

  According to the reduction gear having the first feature or the second feature of the present invention, the internal gear is housed rotatably in the housing, so that the device can be miniaturized. Furthermore, the internal gear and the output shaft, or the carrier and the output shaft are integrally formed of the same material, or even if they are separate members, the coaxiality accuracy is improved and the accuracy varies. Can be suppressed.

  In addition, according to the speed reducer having the third feature of the present invention, the internal gear and at least a part of the power transmission mechanism can be formed as a single part at the same time in an integrated shape, which is excellent in cost and built-in. Accuracy can also be improved. Even if the parts are not the same, the shape for connecting the members constituting a part of the power transmission mechanism by press-fitting or the like can be integrally formed with the internal gear, so that the cost and the mounting accuracy can be reduced. Will also be excellent.

  According to the speed reducer having the fourth feature of the present invention, the movement in the thrust direction can be regulated by the regulating member, and when an external force in the thrust direction is applied to the output shaft, the torque loss is reduced. Can be reduced.

  According to the speed reducer having the fifth feature of the present invention, by forming a feed screw mechanism on the output shaft of the speed reducer, the sliding area is reduced, the sliding resistance of the meshing is reduced, and power is transmitted. Efficiency can be increased.

  Furthermore, according to the speed reducer having the sixth feature of the present invention, the pressurizing member moves the axial vibration at the time of reversing the moving direction during the linear motion to a certain direction, thereby enabling high-precision positioning. It becomes possible.

  And according to the speed reducer having the seventh and eighth features of the present invention, the power transmission rate is good and it can be driven with high precision positioning. Including), liquid and gas can be sucked and discharged strictly.

  FIG. 1 is an exploded perspective view showing a main configuration of a speed reducer according to a first embodiment of the present invention, and FIG. 2 is a perspective view showing a state in which a screw as a power transmission structure is integrally formed on an output shaft of an internal gear. FIG. 3 is a perspective view showing an assembled state of the speed reducer of FIG.

  The speed reducer 1 of the present embodiment is configured by incorporating a planetary gear mechanism in a housing 1a having a substantially cylindrical outer shape.

  The sun gear 3 constituting the planetary gear mechanism and acting as the input side is directly connected to the rotating shaft 2 a of the small motor 2. The three planetary gears 4 meshing with the sun gear 3 are rotatably supported (rotated) by a planetary gear shaft 6 disposed between two disk-shaped carrier members 5, and the shafts of the planetary gears 4 are supported. Each planetary gear 4 is configured to revolve around the sun gear 3 by meshing the lower portion in the direction with the internal teeth of the fixed internal gear 7. Further, the upper part of the planetary gear 4 in the axial direction is meshed with an internal tooth of a movable internal gear 8 having a center coaxially with the rotating shaft of the sun gear, and the power is transmitted through the output shaft 8a of the movable internal gear 8. (Rotational force) can be transmitted.

  A convex portion 9 for sliding contact with the inner peripheral wall of the housing 1 a is formed on the outer peripheral wall 8 b of the movable internal gear 8, and the convex portion 9 is on the rotational axis of the movable internal gear 8. It is formed in an annular shape in which the center point is arranged. In the speed reducer 1 of this embodiment, the convex portion 9 formed on the outer peripheral wall 8b of the movable internal gear 8 is in sliding contact with the inner peripheral wall of the housing 1a during driving. Thus, by reducing the sliding area, the sliding resistance can be reduced and the power transmission efficiency can be increased.

  Further, a power transmission structure 11 for transmitting the power of the motor 2 of the speed reducer 1 to other devices and mechanisms is formed at the front end portion of the output shaft 8a formed on the movable internal gear 8 by resin injection molding. It is integrally formed. Thus, by integrally forming the power transmission structure 11 at the tip of the output shaft 8a, the number of parts can be reduced and the cost can be reduced. Furthermore, by forming the power transmission structure 11 integrally, it is possible to improve the mounting accuracy between the output shaft 8a and the power transmission structure 11, and to suppress variations in accuracy.

  In the present embodiment, the power transmission structure 11 is a feed screw structure for converting the rotational motion of the motor 2 into a linear motion, and the outer periphery of the output shaft 8a is on the base end side as shown in FIG. A first stepped portion 17A for arranging the washer 16 as necessary, a screw 11a, and a second stepped portion 17B for arranging a receiving member 14 for the pressurizing spring 15 described later are formed in order from the tip to the tip side. ing.

  The case 2b of the motor 2 and the housing 1a are connected by welding. Specifically, the outer peripheral wall 7a of the fixed internal gear 7 of the present embodiment is formed so as to be fitted while being in sliding contact with the inner peripheral wall of the housing 1a. That is, two engaging projections 7b are formed at the 180 ° symmetrical position of the lower end portion of the outer peripheral wall 7a, and the engaging notch portion 1b formed at the 180 ° symmetrical position at the lower end portion of the housing 1a. The housing 1a is positioned in the circumferential direction and the axial direction, and in this state, the housing 1a and the case 2b of the motor 2 (both made of metal) are welded and fixed together ( (See FIG. 3). In this way, the housing 1a of the reduction gear 1 and the case 2b of the motor 2 are welded by spot welding, laser welding, or the like, thereby reducing the cost of screw processing or the like and improving the joining strength by welding. It is possible to simplify the positioning of the terminals.

  In the speed reducer 1 that has been incorporated in this way, the first stepped portion 17A, the screw 11a, and the second stepped portion 17B of the output shaft 8a of the internal gear 8 are outward from one end of the housing 1a. It is held so that it can rotate freely.

  In the present embodiment, the washer 16 as a restricting member that receives a force in the thrust direction (linear direction) and restricts the movement in the first stepped portion 17A of the output shaft 8a is disposed. Has been.

  Further, a moving member 13 is screwed into the screw portion 11a of the output shaft 5a. The moving member 13 is arranged so as to be capable of linear (reciprocating) movement in the axial direction while being guided by an auxiliary shaft 12 arranged in the housing 1a in parallel with the output shaft 5a.

  A receiving member 14 of a pressurizing spring 15 is fitted into the second step portion 17B of the output shaft 8a, and a pressurizing member that applies constant pressure between the receiving member 14 and the moving member 13 is provided. As shown, a coil-shaped pressurizing spring 15 inserted in the output shaft 8a is interposed.

  In the speed reducer 1 having such a configuration, the motor 2 is driven to rotate the output shaft 8a, whereby the moving member 13 is linearly operated by a feed screw mechanism having a screw integrally formed with the output shaft 8a. Can be made.

  At this time, by forming a feed screw mechanism on the output shaft 8a of the speed reducer 1, the sliding area between the screw portion 2a and the nut of the moving member 13 is reduced, and the sliding resistance of the engagement is reduced, thereby reducing the power transmission efficiency. Can be good.

  Further, by providing a washer 16 as a restricting member on the first stepped portion 17A of the output shaft 8a, the movement in the thrust direction can be restricted by the small inner diameter portion of the washer 16, and the external force in the thrust direction The loss of the rotational torque due to can be reduced.

  Further, the pressurizing spring 15 is disposed between the rotation stopper 14 and the moving member 13 so as to bring the axial vibration (backlash) toward a certain direction, thereby positioning when reversing the moving direction during linear motion. Accuracy can be improved.

  4 is an exploded perspective view showing the configuration of the main part of the reduction gear according to the second embodiment of the present invention, and FIG. 5 is a perspective view showing a state in which a screw as a power transmission structure is integrally formed on the output shaft of the internal gear. FIG.

  Hereinafter, differences between the speed reducer 1 of the present embodiment and the speed reducer of the first embodiment will be described.

  In the present embodiment, the three planetary gears 4 that mesh with the sun gear 3 directly connected to the rotary shaft 2a of the small motor 2 are the carrier member 5 in which the disk-shaped carrier member 5 and the output shaft 5a are formed. Each planetary gear is supported by a planetary gear shaft 6 disposed between the bottom surface of the shaft and the planetary gear 4 so as to be freely rotatable (spinned). 4 is configured to revolve around the sun gear 3, and is configured to be able to transmit power (rotational force) via the output shaft 5a of the carrier member 5 '.

  A power transmission structure 11 for transmitting the power of the motor 2 of the speed reducer 1 to another device or mechanism is integrated with the tip of the output shaft 5a formed on the carrier member 5 'by resin injection molding. Is formed. In this way, by integrally forming the power transmission structure 11 at the tip of the output shaft 5a, the number of parts can be reduced and the cost can be reduced. Furthermore, by forming them integrally, it is possible to improve the mounting accuracy between the output shaft 5a and the power transmission structure 11, and to suppress variations in accuracy.

  In the present embodiment, the power transmission structure 11 is a feed screw structure for converting the rotational motion of the motor 2 into a linear motion, and the outer periphery of the output shaft 5a is on the base end side as shown in FIG. A first stepped portion 17A for arranging the washer 16 as necessary, a screw 11a, and a second stepped portion 17B for arranging the receiving member 14 for the pressurizing spring 15 are formed in order from the tip to the tip side. .

  The speed reducer 1 of the present embodiment projects the first stepped portion 17A, the screw 11a, and the second stepped portion 17B of the output shaft 5a of the carrier member 5 ′ outward from one end portion of the housing 1a. The case 2b of the motor 2 and the housing 1a are connected by welding while being held rotatably.

  Also in this embodiment, the first step portion 17A of the output shaft 8a is provided with a washer 16 as a restricting member that receives a force in the thrust direction (linear direction) and restricts the movement in that direction. Has been.

  Further, a moving member 13 is screwed into the screw portion 11a of the output shaft 5a. The moving member 13 is arranged so as to be capable of linear (reciprocating) movement in the axial direction while being guided by an auxiliary shaft 12 arranged in the housing 1a in parallel with the output shaft 5a.

  The receiving member 14 is inserted into the second step portion 17B of the output shaft 5a, and is inserted into the output shaft 5a as a pressurizing member between the rotation stopper 14 and the moving member 13. The coiled pressurizing spring 15 is interposed.

  And the speed reducer 1 of this embodiment having such a configuration drives the motor 2 to rotate the carrier member 5 ′ on which the output shaft 5a is formed, whereby the screw integrally formed on the output shaft 5a. The moving member 13 can be linearly moved by a feed screw mechanism having

  By forming the feed screw mechanism on the output shaft 8a of the speed reducer 1 in this way, the sliding area between the screw portion 2a and the nut of the moving member 13 is reduced, and the sliding resistance of the engagement is reduced, thereby reducing the power transmission efficiency. Can be good.

  Also in the present embodiment, by providing the washer 16 as the restricting member on the first step portion 17A of the output shaft 8a, the movement in the thrust direction can be restricted by the inner diameter portion thereof. The loss of rotational torque due to the external force can be reduced.

  Further, positioning is performed when the moving direction is reversed during linear movement by arranging the pressure spring 15 between the receiving member 14 and the moving member 13 to bring the axial vibration (backlash) toward a certain direction. Accuracy can be improved.

  And the speed reducer comprised in this way has a favorable power transmission rate, and can be driven by highly accurate positioning. Therefore, by using the speed reducer of the above-described embodiment as a linear motion mechanism of a plunger for sucking and discharging liquid or gas, and adjusting the fluid flow rate by causing the moving member to act as an adjustment member for adjusting the fluid flow rate ( (Including blocking) can be performed strictly.

  In addition, this invention is not limited to embodiment mentioned above, A various change is possible as needed.

  For example, the power transmission mechanism is not limited to a feed screw as in this embodiment, and may be a cam structure. Moreover, although the said power transmission structure is integrally formed in the rotation internal gear or the carrier member by resin injection molding, the method of integral formation is not restricted to this. Further, the power transmission structure is not formed integrally with the rotating internal gear in the first embodiment and the carrier member in the second embodiment, and another member having a screw structure is integrated with the rotating internal gear or the carrier member. It may be formed by bonding to.

  It is possible to omit the arrangement of the restricting member that is arranged in the first step portion 17A and receives the force in the thrust direction (linear direction) and restricts the movement in that direction. Further, the restricting member is not limited to the washer of the present embodiment, and may be a C ring, for example.

  Further, a shaft support member that rotatably holds the output shaft 8a and converts rotational motion into linear motion may be disposed on the inner peripheral wall of the housing 1a. For example, examples of the shaft support member include a ball bearing, a cam, and a screw arranged in a ring shape so as to support the cylindrical base portion of the output shaft 8a.

The disassembled perspective view which shows the principal part structure in embodiment of the reduction gear of this invention The perspective view which shows the state in which the screw as a power transmission structure was integrally formed in the output shaft of the internal gear The perspective view which shows the assembly state of the reduction gear of FIG. The disassembled perspective view which shows the principal part structure in another embodiment of the reduction gear of this invention. The perspective view which shows the state by which the screw as a power transmission structure was integrally formed by the output shaft formed in the carrier

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reducer 1a Housing 1b Notch for engagement 2 Motor 2a Rotating shaft 2b Case 3 Sun gear 4 Planetary gear 5 (Disk-shaped) Carrier member 5 '(Output shaft is formed) Carrier member 6 Planetary gear shaft 7 Fixed Internal gear 7a Outer peripheral wall 7b Engaging projection 8 Movable internal gear 8a Outer peripheral wall 9 Convex portion 11 Power transmission structure 11a Screw 12 Auxiliary shaft 13 Moving member 14 Anti-rotation 15 Pressure spring 16 Washer 17A First step portion 17B Second Step

Claims (8)

In a housing connected to the motor case of the motor, a sun gear directly connected to the motor's rotating shaft, a plurality of planetary gears meshed with the sun gear, meshed with the planetary gear, and coaxially centered with the sun gear's rotating shaft A reduction gear provided with an internal gear having
The planetary gear is rotatably held, the internal gear is rotatably held, an output shaft formed on the internal gear is rotatably held by the housing, and power is transmitted to the output shaft. A speed reducer characterized in that the structure is integrally formed. In a housing connected to the motor case of the motor, a sun gear directly connected to the motor's rotating shaft, a plurality of planetary gears meshed with the sun gear, meshed with the planetary gear, and coaxially centered with the sun gear's rotating shaft A reduction gear provided with an internal gear having
The internal gear is fixed to the housing, the planetary gear is held by a carrier that can rotate and revolve around a sun gear, and an output shaft formed on the carrier is rotatably held by the housing. The speed reducer is characterized in that a power transmission structure is integrally formed on the distal end side of the output shaft. The reduction gear according to claim 1 or 2, wherein the internal gear is formed by injection molding of a resin material. The output shaft having the power transmission structure has a restricting member for restricting movement in a linear direction, and is rotatably held by the housing. The reducer described. 5. The speed reducer according to claim 1, wherein the power transmission mechanism of the output shaft has a feed screw or a cam structure for converting rotational motion into linear motion. 2. The apparatus according to claim 1, further comprising: a moving member that is disposed on the output shaft and is linearly movable in the axial direction; and a pressurizing member that applies pressure to the moving member. Item 6. The speed reducer according to any one of Items 5 to 6. The speed reducer according to claim 6, wherein the moving member is an adjusting member that adjusts a fluid flow rate. The speed reducer according to claim 6 or 7, wherein the speed reducer is a linear motion mechanism of a plunger for adjusting a flow rate of a fluid or gas sucked or discharged.

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