JP2018165532A - Gear speed reducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speed reducer capable of improving transmission efficiency by reducing backlash of a tooth portion of an internal tooth type output gear and a tooth portion of an external tooth type input gear without degrading effectiveness of a spring.SOLUTION: An internal tooth portion 25A of an internal tooth-type output gear 25 coaxial with a rotation shaft core X and an external tooth portion 30A of an input gear 30 coaxial with an eccentric shaft core Y are partially engaged, and an eccentric member 26 provided with an eccentric bearing face 26E supporting the input gear 30 rotatably on the eccentric shaft core Y, is disposed. An energization member 27 for applying energization force to engage the external tooth portion 30A of the input gear 30 with the internal tooth portion 25A of the output gear 25 is composed of a flat spring material in which an angle from an action point P in which the energization force is acted to a supporting portion PB, is over 90 degrees on the eccentric shaft core Y as a center.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a gear reduction device that engages an internal gear and an external gear having a smaller number of teeth to realize a reduction due to a difference in the number of teeth.

  The gear reduction mechanism having the above configuration is called an inscribed planetary reduction mechanism or a hypocycloid reduction mechanism.

  As a specific configuration of this gear reduction device, Patent Document 1 discloses that an internal gear (a ring gear in the literature) is arranged coaxially with a rotary shaft, and an external gear (an inner gear in the literature) is parallel to the rotary shaft. A technique is shown that includes an eccentric member (an eccentric ring in the literature) that is arranged on an eccentric shaft core and a coaxial core and rotatably supports an external gear around the eccentric shaft core.

  In this patent document 1, by providing a spring member that protrudes and biases the external gear in the eccentric direction, the tooth portion of the external gear is engaged with the tooth portion of the internal gear, and the backlash is maintained. The beating sound caused by the sound is suppressed.

  In Patent Document 1, the eccentric member is driven to rotate around the rotation axis to cause the eccentric shaft to revolve around the rotation axis, and the external gear engages with the internal gear along with this revolution. In this state, the external gear is moved while rotating along the inner periphery of the internal gear. As a result, at the timing when the external gear is rotated once, the internal gear and the external gear rotate relative to each other by an angle corresponding to the difference in the number of teeth between the internal gear and the external gear, and a large reduction ratio is obtained. Realization of slowdown.

JP 2016-44627 A

  In the gear reduction device having this configuration, it is important to reliably maintain the internal gear and the external gear in an occlusal shape. For this reason, for example, it is conceivable to use a spring member having a large spring constant described in Patent Document 1. However, when a spring member with a large spring constant is used, the tooth part of the internal gear and the tooth part of the external gear are in strong pressure contact, and therefore the transmission efficiency is likely to decrease due to friction loss during transmission. It becomes.

  On the other hand, when a spring member having a small spring constant is used, the tooth portion of the internal gear and the tooth portion of the external gear are rubbed with each other due to vibration transmitted from the outside, and the tooth surface Wear is also likely to occur. In addition, in the case where the spring member is greatly deformed in this way, the spring is broken by a load that repeatedly acts.

  For this reason, it is possible to reduce the backlash between the tooth portion of the internal gear type output gear and the tooth portion of the external gear type input gear by the biasing force of the spring, and the transmission efficiency can be increased. A reduction gear is required.

The feature of the present invention is that the internal gear type output gear is arranged on the rotating shaft core and the coaxial core, and the eccentric shaft core is arranged coaxially with the eccentric shaft core having a smaller number of teeth than the output gear and parallel to the rotating shaft core. Thus, an external gear type input gear that meshes with the output gear and an eccentric bearing surface that rotatably supports the input gear around the eccentric shaft core are supported to revolve around the rotary shaft core. An eccentric member, and an urging member supported by the eccentric member for applying an urging force for engaging the tooth portion of the input gear with the tooth portion of the output gear,
The biasing member is formed on the eccentric member, and an operating point for applying a biasing force to a region in an eccentric direction in which the eccentric shaft core is eccentric with respect to the rotation shaft core on the inner peripheral side of the input gear. And a support point in contact with the support, and an angle from the action point to the support point with respect to the eccentric shaft center is more than 90 degrees.

According to this characteristic configuration, since the urging force of the urging member acts in a direction in which the tooth portion of the output gear and the tooth portion of the input gear are engaged, backlash can be suppressed. Further, in this characteristic configuration, since a long plate-shaped spring material can be used as the urging member, for example, a plate-shaped spring material having a spring constant necessary for engaging the tooth portion of the output gear and the tooth portion of the input gear is used. Even if it is set, the plate-like spring material will be elastically deformed as a whole, and there will be no breakage due to the action of local stress.
Therefore, a reduction gear that can reduce backlash between the tooth portion of the internal gear type output gear and the tooth portion of the external gear type input gear by the biasing force of the spring and can increase the transmission efficiency is configured. It was.

  As another configuration, the support may be provided on a side opposite to the eccentric direction across the rotation axis.

  According to this, by forming the support body on the eccentric member, it is possible to use a long plate-shaped spring material arranged in a region extending across the position facing the eccentric shaft core.

  As another configuration, a part of the eccentric bearing surface may be formed by the outer peripheral surface of the support.

  According to this, it becomes possible to share a part of the part forming the eccentric bearing surface of the eccentric member as the support. Further, a plate-shaped spring material curved in a U-shape is used as the urging member, both ends of the plate-shaped spring material are brought into contact with the support, and the most projecting position in the center of the plate-shaped spring material is defined as an action point. It is also possible to do.

  As another configuration, the eccentric member may be formed with a restricting portion in the eccentric direction region for restricting displacement of the tooth portion of the input gear in a direction away from the tooth portion of the output gear.

  According to this, in the region where the tooth portion of the output gear and the tooth portion of the input gear mesh, when the external force that displaces the input gear acts in the direction in which these tooth portions are separated, the restricting member restricts the displacement. Therefore, the inconvenience that the tooth portions are separated can be suppressed.

As another configuration, the restricting portion includes an arc-shaped restricting surface that bulges outward with respect to the eccentric shaft core, and the biasing member bulges outward with respect to the eccentric shaft core as described above. The action point is formed in a bulging region having a radius of curvature smaller than the radius of curvature of the restriction surface,
The biasing member may be disposed between the restricting portion and the input gear so that the action point is disposed on the outer peripheral side of the restricting surface.

  According to this, when the plate-shaped spring material constituting the urging member is disposed between the restricting portion and the inner peripheral side of the input gear, the plate-shaped spring material is disposed between the bulging area and the regulating surface. A gap is created, and the point of action formed in the bulging region is brought into contact with the inner peripheral side of the input gear, so that the urging force of the urging member can be applied. In particular, in this configuration, when the input gear is displaced in the direction of the rotation axis due to the action of an external force or the like, the displacement of the input gear is restricted by reaching a state where the urging member comes into contact with the restriction surface of the restriction part, The inconvenience that the tooth part of the input gear is separated from the tooth part of the output gear is suppressed.

It is sectional drawing of a valve opening / closing timing control apparatus. It is the II-II sectional view taken on the line of FIG. It is the III-III sectional view taken on the line of FIG. It is a disassembled perspective view which shows an output gear, an input gear, and an eccentric member. It is sectional drawing which shows the shape of the spring body of another embodiment (a). It is sectional drawing which shows the shape of the spring body of another embodiment (b).

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Basic configuration]
As shown in FIG. 1, a drive-side rotator A that rotates synchronously with the crankshaft 1 of the engine E, a driven-side rotator B that rotates integrally with the intake camshaft 2 around the rotation axis X, and a phase control motor The valve opening / closing timing control device 100 is configured to include a phase adjustment unit C formed of a gear reduction device so as to set the relative rotation phase between the driving side rotating body A and the driven side rotating body B by the driving force of M. .

  The engine E is configured as a four-cycle type in which pistons 4 are accommodated in a plurality of cylinders 3 formed in a cylinder block, and the pistons 4 are connected to a crankshaft 1 by connecting rods 5. A timing belt 6 (or a timing chain or the like) is wound around the output sprocket 1S of the crankshaft 1 of the engine E and the drive sprocket 11S of the drive side rotator A.

  As a result, when the engine E is in operation, the entire valve opening / closing timing control device 100 rotates about the rotation axis X. In addition, the phase control motor M drives the phase adjustment unit C to achieve a relative rotational phase displacement that causes the driven-side rotator A to displace the driven-side rotator B in the same or opposite direction as the rotation direction (this operation) The form will be described later). Due to the displacement of the relative rotational phase, the control of the opening / closing timing (opening / closing timing) of the intake valve 2B by the cam portion 2A of the intake camshaft 2 is realized.

  The operation in which the driven-side rotator B is displaced in the same direction as the rotational direction of the drive-side rotator A is referred to as an advance angle operation, and the intake air compression ratio is increased by the advance angle operation. In addition, an operation in which the driven-side rotator B is displaced in the direction opposite to the drive-side rotator A (an operation in the direction opposite to that described above) is referred to as retarded angle operation, and the intake air compression ratio is reduced by this retarded angle operation.

[Valve opening / closing timing control device]
As shown in FIGS. 1 to 3, the drive-side rotator A is configured by fastening an outer case 11 having a drive sprocket 11 </ b> S formed on the outer periphery and a front plate 12 with a plurality of fastening bolts 13. The outer case 11 is a bottomed cylindrical mold having an opening at the bottom.

  An intermediate member 20 as a driven-side rotator B and a phase adjusting unit C are accommodated in the inner space of the outer case 11.

  The intermediate member 20 constituting the driven side rotating body B includes a support wall portion 21 connected to the intake camshaft 2 in a posture orthogonal to the rotation axis X, and a cylindrical intake camshaft 2 centered on the rotation axis X. A cylindrical wall portion 22 that protrudes in a direction away from is integrally formed.

  The intermediate member 20 is fitted in a relatively rotatable manner in a state where the outer peripheral surface of the cylindrical wall portion 22 is in contact with the inner peripheral surface of the outer case 11, and is connected by a connecting bolt 23 that is inserted into the central through hole of the support wall portion 21. It is fixed to the end of the intake camshaft 2.

  The phase control motor M (electric motor) is supported by the engine E by the support frame 7 so that the output shaft Ma is disposed coaxially with the rotary shaft X. The output shaft Ma is provided with a pair of engagement pins 8 in a posture orthogonal to the rotation axis X.

[Phase adjuster]
As shown in FIGS. 1 to 4, the phase adjuster C includes an intermediate member 20, an output gear 25 formed on the inner peripheral surface of the cylindrical wall portion 22 of the intermediate member 20, an eccentric member 26, and a first bearing. 28, a second bearing 29, an input gear 30, and an Oldham coupling Cx.

  The output gear 25 is configured as an internal tooth type in which a plurality of internal tooth portions 25A are formed on the inner periphery of an annular body centered on the rotation axis X. The input gear 30 is configured as an external tooth type in which a plurality of external tooth portions 30A are formed around an eccentric shaft core Y in a posture parallel to the rotation shaft core X.

  In this phase adjustment unit C, the number of teeth of the external tooth portion 30A of the input gear 30 is smaller by one than the number of teeth of the internal tooth portion 25A of the output gear 25. As will be described later, the phase adjustment unit C is supported by the input gear 30 so as to be rotatable about the eccentric shaft core Y, so that a part of the external gear portion 30A of the input gear 30 becomes the internal gear portion of the output gear 25. It bites into a part of 25A.

  The eccentric member 26 is formed with a center bearing surface 26S centering on the rotation axis X on the outer end side (the side far from the intake camshaft 2) in the direction along the rotation axis X, and the inner end side (intake camshaft). An eccentric bearing surface 26E is formed on the outer peripheral surface centering on the eccentric shaft core Y that is eccentric in a posture parallel to the rotation shaft core X.

  A spring body 27 is attached to the eccentric member 26 as an urging member for obtaining an urging force for engaging the outer tooth portion 30A of the input gear 30 with the inner tooth portion 25A of the output gear 25. This spring body 27 is formed into an annular shape with a part opened by curving a plate spring material such as spring steel, and an action point PA for applying a biasing force to an intermediate position in the circumferential direction is formed. A support point PB is formed on the surface. In particular, as shown in FIG. 2, the spring body 27 having an eccentric axis Y as a center and an angle from the action point PA to the support point PB exceeding 90 degrees is used.

  The eccentric bearing surface 26E is formed in a region opposite to the eccentric direction in which the eccentric shaft core Y is eccentric with respect to the rotation shaft core X, and this region serves as the support body 26Q. In particular, the eccentric bearing surface 26E also used as the support 26Q is formed at a position slightly displaced in the eccentric direction so as to allow the input gear 30 to be displaced in the eccentric direction. Although the eccentric bearing surface 26E opposite to the eccentric direction and the inner circumference and the gap of the second bearing 29 are slight, the intervals are exaggerated in FIGS.

  A restricting portion 26 </ b> R is formed in the eccentric direction of the eccentric member 26. A regulating surface 26Rs that is coaxial with the eccentric bearing surface 26E but has a smaller diameter than the eccentric bearing surface 26E is formed on the outer peripheral side of the regulating portion 26R, and contact surfaces 26Rp are formed at both ends in the circumferential direction. Yes. In particular, the restricting portion 26 </ b> R restricts the displacement of the external gear portion 30 </ b> A of the input gear 30 in the direction away from the internal gear portion 25 </ b> A of the output gear 25, and the restricting surface 26 </ b> Rs and the inner periphery of the second bearing 29. A sufficient interval for the arrangement of the spring body 27 is set between the two.

  As shown in FIG. 2, the action point PA is arranged on the outer peripheral surface side (outside the regulation surface 26Rs) of the regulating portion 26R, and the spring body 27 is arranged in a positional relationship in which the support points PB at both ends abut against the support body 26Q. The In particular, when arranged in this manner, the spring body 27 is elastically deformed in advance by a predetermined amount to apply an urging force from the action point PA toward the eccentric direction.

  As described above, the regulation surface 26Rs is formed in a circular arc shape coaxial with the eccentric bearing surface 26E, and a portion of the spring body 27 that is disposed radially outward from the regulation surface 26Rs is a radius of curvature of the regulation surface 26Rs. It is formed as a bulging region with a smaller radius of curvature. Thereby, a gap is formed between the bulging area and the regulation surface 26Rs.

  On the inner periphery of the eccentric member 26, a pair of engagement grooves 26 </ b> T that can be engaged with each of the pair of engagement pins 8 of the phase control motor M are formed in a posture parallel to the rotational axis X.

  Ball bearings are used for the first bearing 28 and the second bearing 29, and the inner periphery (inner race) of the first bearing 28 is externally fitted to the center bearing surface 26S. The outer periphery (outer race) of the first bearing 28 Is fitted into the holding space in the central portion of the front plate 12 so that the eccentric member 26 is supported to be rotatable about the rotation axis X.

  Further, the inner circumference (inner race) of the second bearing 29 is fitted on the eccentric bearing surface 26 </ b> E, and the outer circumference (outer race) of the second bearing 29 is fitted on the inner circumference of the input gear 30. As a result, the input gear 30 is supported so as to be rotatable (rotatable) about the eccentric axis Y. As a result of the input gear 30 being arranged at the eccentric position in this way, a part of the external tooth portion 30A of the input gear 30 is engaged with a part of the internal tooth portion 25A of the output gear 25. The position of the second bearing 29 is fixed by a fixing ring 31.

  Ball bearings are used for the first bearing 28 and the second bearing 29, but bushes may be used. Furthermore, a configuration in which the input gear 30 is directly supported rotatably with respect to the eccentric bearing surface 26E without using a bearing may be employed.

[Phase adjuster: Oldham coupling]
As shown in FIGS. 1 and 3, the Oldham coupling Cx includes a central annular portion 41 and a pair of external parts projecting radially outward from the annular portion 41 along a first direction (left-right direction in FIG. 3). A plate-like joint member 40 in which an engagement arm 42 and an internal engagement arm 43 that protrudes radially outward along a direction (vertical direction in FIG. 3) orthogonal to the first direction from the annular portion 41 are integrally formed. It consists of Each of the pair of internal engagement arms 43 is formed with an engagement recess 43 a that is continuous with the opening of the annular portion 41.

  In the outer case 11, a pair of guide groove portions 11 a extending in the radial direction about the rotation axis X from the inner space to the outer space of the outer case 11 is formed in a through groove shape at the opening edge portion where the front plate 12 contacts. Is formed. The groove width of the guide groove portion 11 a is set to be slightly wider than the width of the external engagement arm 42.

  A pair of engaging projections 30T are integrally formed on the end face of the input gear 30 that faces the front plate 12. The engagement width of the engagement protrusion 30T is set slightly narrower than the engagement width of the engagement recess 43a of the internal engagement arm 43.

  The joint member 40 can be displaced in the first direction (left and right direction in FIG. 3) in which the external engagement arm 42 extends with respect to the outer case 11, and the engagement concave portion of the internal engagement arm 43 with respect to the joint member 40. The input gear 30 is displaceable in a second direction (vertical direction in FIG. 3) along the formation direction of 43a.

[Arrangement of each part of valve timing control device]
In the assembled valve opening / closing timing control device 100, as shown in FIG. 1, a support wall portion 21 of the intermediate member 20 is connected to an end portion of the intake camshaft 2 by a connecting bolt 23, and these rotate integrally. The eccentric member 26 is supported by the first bearing 28 so as to be rotatable relative to the front plate 12 about the rotational axis X. As shown in FIGS. 1, 2, and 4, the input gear 30 is supported via the second bearing 29 on the eccentric bearing surface 26 </ b> E of the eccentric member 26. As a result, the input gear 30 is supported so as to be rotatable about the eccentric axis Y, and a part of the outer tooth part 30A is engaged with a part of the inner tooth part 25A of the output gear 25.

  Further, as shown in FIG. 3, the external engagement arm 42 of the Oldham joint Cx engages with the pair of guide groove portions 11a of the outer case 11, and the input gear 30 enters the engagement recess 43a of the internal engagement arm 43 of the Oldham joint Cx. The engaging protrusions 30T are engaged.

  Further, as shown in FIGS. 1 and 3, the pair of engagement pins 8 formed on the output shaft Ma of the phase control motor M engages with the engagement groove 26 </ b> T of the eccentric member 26.

  Then, as shown in FIG. 2, the action point PA is disposed on the outer peripheral surface side (outside the restriction surface 26Rs) of the restricting portion 26R, and the spring body 27 is in a positional relationship in which the support points PB at both ends abut against the support member 26Q. Be placed. Of the spring body 27, the position of the portion disposed on the outer periphery of the restricting portion 26 </ b> R is restricted in the direction along the rotational axis X by the fixing ring 31.

[Operation mode of phase adjuster]
Although not shown in the drawing, the phase control motor M is controlled by a control device configured as an ECU. The engine E is provided with sensors capable of detecting the rotation speed (the number of rotations per unit time) of the crankshaft 1 and the intake camshaft 2 and the respective rotation phases, and the detection signals of these sensors are control devices. To enter.

  The control device maintains the relative rotational phase by driving the phase control motor M at a speed equal to the rotational speed of the intake camshaft 2 when the engine E is in operation. On the other hand, the relative rotational phase displacement is realized by increasing or decreasing the rotational speed of the phase control motor M with reference to the rotational speed of the intake camshaft 2.

  When the phase control motor M rotates at the same speed as the outer case 11 (the same speed as that of the intake camshaft 2), the meshing position of the external tooth portion 30A of the input gear 30 with respect to the internal tooth portion 25A of the output gear 25 changes. Therefore, the relative rotational phase of the driven side rotator B with respect to the drive side rotator A is maintained.

  On the other hand, by driving and rotating the output shaft Ma of the phase control motor M at a speed higher or lower than the rotational speed of the outer case 11, the eccentric shaft core Y revolves around the rotation shaft core X in the phase adjustment unit C. Due to this revolution, the meshing position of the input gear 30 with respect to the inner tooth portion 25A of the output gear 25 with respect to the outer tooth portion 30A is displaced along the inner periphery of the output gear 25, and the displacement between the input gear 30 and the output gear 25 is accompanied by this displacement. A rotational force acts between them. That is, a rotational force centered on the rotational axis X acts on the output gear 25, and a rotational force that attempts to rotate about the eccentric shaft core Y acts on the input gear 30.

  As described above, the number of teeth of the external gear portion 30A of the input gear 30 is set to be one less than the number of teeth of the internal gear portion 25A of the output gear 25. Even when only one revolution is made around the core X, the output gear 25 rotates only by one tooth angle with respect to the input gear 30, and transmission with a large reduction ratio is realized.

  The input gear 30 does not rotate with respect to the outer case 11 because its engaging protrusion 30T engages with the engaging recess 43a of the internal engaging arm 43 of the joint member 40, and rotational force acts on the output gear 25. To do. Due to the action of the rotational force, the intermediate member 20 together with the output gear 25 rotates about the rotation axis X with respect to the outer case 11. As a result, the relative rotational phase between the driving side rotating body A and the driven side rotating body B is displaced, and the opening / closing timing by the intake camshaft 2 is set.

  When the eccentric shaft core Y of the input gear 30 revolves around the rotation shaft core X, the joint member 40 of the Oldham joint Cx is externally engaged with the outer case 11 as the input gear 30 is displaced. The arm 42 is displaced in the extending direction (first direction), and the input gear 30 is displaced in the extending direction (second direction) of the internal engagement arm 43.

  The spring body 27 applies an urging force in the direction in which the single action point PA is displaced in the eccentric direction with reference to the pair of support points PB in the state of being arranged in the posture shown in FIG. The state where the external tooth portion 30A of the input gear 30 is engaged with the internal tooth portion 25A is maintained.

  Further, since the spring body 27 is formed by gently curving a plate spring material, for example, assuming a leaf spring having a smaller spring size and the same spring constant as the spring body 27, the small leaf spring is elastically deformed. In such a case, the overall deformation amount may be large, leading to breakage. In particular, in a configuration in which a specific part is elastically deformed, stress concentrates on the specific part, and as a result, breakage easily occurs. On the other hand, in the spring body 27 of this embodiment, when the elastic body 27 is elastically deformed, the entire body is gently bent, so that the durability is improved without causing inconvenience such as breakage.

  In this spring body 27, by setting a spring constant so as to obtain a required urging force, the outer tooth portion 30A of the input gear 30 is properly engaged with the inner tooth portion 25A of the output gear 25, and the backlash is reduced. By doing so, responsiveness is improved and transmission with good efficiency is enabled.

  In addition, when a large force is applied in the direction of separating the external tooth portion 30A of the input gear 30 from the internal tooth portion 25A of the output gear 25, the spring body 27 contacts the pair of contact surfaces 26Rp of the restricting portion 26R. As a result, the amount of bending of the spring body 27 can be reduced, and the displacement of the input gear 30 can be strongly suppressed. When a force larger than this is applied, the portion of the operating point PA of the spring body 27 is brought into contact with the restricting surface 26Rs of the restricting portion 26R as the input gear 30 is displaced, and the input gear 30 is reliably displaced. To stop.

[Another embodiment]
In addition to the above-described embodiments, the present invention may be configured as follows (the components having the same functions as those of the embodiments are given the same numbers and symbols as those of the embodiments).

(A) As shown in FIG. 5, the spring body 27 is formed in a C-shape, and an action point PA is provided on one side near both ends, and a support point PB is set on the other side.

  In this other embodiment (a), the other configurations except for the spring body 27 are the same as in the embodiment, and a force acts in a direction to separate the outer tooth portion 30A of the input gear 30 from the inner tooth portion 25A of the output gear 25. In this case, the action point PA is simply displaced toward the support point PB. This reduces backlash, improves responsiveness, and achieves transmission with good efficiency.

(B) As shown in FIG. 6, an elliptical annular material is used for the spring body 27, and an action point PA is provided on one side in the major axis direction of the ellipse, and a support point PB is set on the other side.

  In this other embodiment (b), the configuration other than the spring body 27 is the same as that of the embodiment, and a force acts in a direction to separate the outer tooth portion 30A of the input gear 30 from the inner tooth portion 25A of the output gear 25. In this case, the entire spring body 27 is elastically deformed so that the minor axis direction of the ellipse swells, and the action point PA is displaced toward the support point PB. This reduces backlash, improves responsiveness, and achieves transmission with good efficiency.

(C) The shape of the spring body 27 is not limited to the shape shown in the embodiment or the shape shown in another embodiment (a). For example, one end is fixed to the eccentric member 26 and the other end is May be in a free state. Furthermore, a wire such as a piano wire may be used as the spring body 27.

(D) In the embodiment, the gear reduction device that constitutes the phase adjustment unit C is used as, for example, a reduction device for setting an inclination posture of a seat back of a seat such as a driver's seat of a vehicle. Thus, the part used with the reduction gear is not limited to the setting of the inclination posture of the seat back of the vehicle, but may be used for the reduction device of the robot arm, for example.

  INDUSTRIAL APPLICABILITY The present invention can be used for a gear reduction device having a configuration in which an internal gear and an external gear having a smaller number of teeth are engaged.

25 Output gear 25A Internal teeth (tooth)
26 Eccentric member 26E Eccentric bearing surface 26S Center bearing surface 26Q Support body 26R Restricting portion 26Rs Restricting surface 27 Spring body (biasing member)
30 Input gear 30A External tooth part (tooth part)
X Rotating shaft core Y Eccentric shaft core PA Action point PB Support point

Claims (5)

An internal gear-type output gear disposed on the rotating shaft core and the coaxial core, and an eccentric shaft core having a smaller number of teeth than the output gear and parallel to the rotating shaft core, and disposed on the coaxial core to the output gear. An externally engaged input gear, an eccentric member having an eccentric bearing surface that supports the input gear so as to rotate about the eccentric shaft core, and an eccentric member supported to revolve about the rotating shaft core, An urging member supported by the eccentric member for applying an urging force for engaging a tooth portion of the input gear with a tooth portion of the output gear;
The biasing member is formed on the eccentric member, and an operating point for applying a biasing force to a region in an eccentric direction where the eccentric shaft core is eccentric with respect to the rotation shaft core on the inner peripheral side of the input gear. And a support point that comes into contact with the support, and a gear reduction device that is formed of a plate-shaped spring material having an angle from the action point to the support point that is greater than 90 degrees around the eccentric shaft core.   The gear reduction device according to claim 1, wherein the support body is provided on a side opposite to the eccentric direction across the rotation axis.   The gear reduction device according to claim 2, wherein a part of the eccentric bearing surface is formed by an outer peripheral surface of the support body.   The eccentric member has a restricting portion for restricting displacement in a direction in which the tooth portion of the input gear is separated from the tooth portion of the output gear in the region in the eccentric direction. A gear reduction device according to claim 1. The restricting portion includes an arc-shaped restricting surface that bulges outward with reference to the eccentric shaft core, and the urging member bulges outward with respect to the eccentric shaft core to cause a radius of curvature of the restricting surface. Forming the point of action in a bulging region with a smaller radius of curvature;
The gear reduction device according to claim 4, wherein the urging member is disposed between the restriction portion and the input gear so that the action point is disposed on an outer peripheral side of the restriction surface.

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