JP5336822B2 - Gear device and electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gear device capable of solving a sealing problem as well when biasing a gear shaft with an elastic body to an axial direction with the elastic body interposed between a gearbox cover and the gear shaft. <P>SOLUTION: The gearbox 10 transmits power from one shaft 2 to the other shaft 12 using gears 1, 3. At least a bearing 2a on one end of the one shaft 2 is supported to a case 4 of the gearbox 10 by a detachable cover 6. The elastic body 7 for biasing the one shaft 2 to an axial direction and sealing between the cover 6 and the case 4 is provided between the cover 6 and the bearing 2a and case 4. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a gear device that includes a worm speed reducer and transmits power from one shaft to the other shaft using a gear, and an electric power steering device using the gear device.

  In gear devices, especially worm speed reducers, the worm shaft, which is one of its shafts, is well meshed with the worm wheel and reduces noise (rattle noise) caused by vibration in the gap range between the tooth surfaces. For this reason, the worm shaft is biased in the axial direction.

  Patent Documents 1 to 7 describe an elastic body that performs such urging. In this, a lid that can be attached to and detached from the case of the gear device is provided. The thing which provided the elastic body between is also contained.

  On the other hand, Patent Documents 8 and 9 describe an O-ring (symbol 5c in each document) that seals the exterior between a lid that can be attached to and detached from the case of the gear device and the case. It is suggested that some seal is necessary when using.

  However, in Patent Documents 1, 2, 4, and 5 using a lid, no description regarding such a seal could be found.

JP 2003-327143 A (reference numeral 31 in FIG. 2) JP 2008-126873 A (reference numeral 36 in FIG. 3) Japanese Patent Laying-Open No. 2005-112047 (reference numeral 23 in FIG. 1) JP 2007-247734 A (reference numeral 17 in FIG. 2) Japanese Patent Laying-Open No. 2001-010512 (reference numeral 21 in FIG. 2) JP-A-10-281235 (reference numeral 9 in FIG. 1) Japanese Patent Laid-Open No. 2001-130423 (reference numeral 3 in FIG. 1) Japanese Patent Laying-Open No. 2007-130423 (reference numeral 5c in FIG. 1) Japanese Patent Laying-Open No. 2008-039049 (reference numeral 5c in FIG. 1)

  The present invention is intended to ameliorate the above problem, and when an elastic body is interposed between the lid of the gear device and the gear shaft and the gear shaft is urged in the axial direction by the elastic body, at the same time, It is an object of the present invention to provide a gear device that can solve the problem and an electric power steering device using the gear device.

The gear device of the present invention is a gear device that transmits power from one shaft to the other shaft using a gear, and supports a bearing at least one end of the one shaft with a cover that can be attached to and detached from the case of the gear device. An elastic body that urges the one shaft in an axial direction and seals between the lid and the case between the lid and the bearing and the case, and the gear includes a worm and a worm. The wheel is characterized in that the one shaft is a worm shaft that supports the worm, and the gear device is used to drive a steering output shaft of an electric power steering device .

  The electric power steering device of the present invention is characterized in that the gear device is a worm reducer, and the worm reducer is used for driving a steering output shaft.

The gear device of the present invention is a gear device that transmits power from one shaft to the other shaft using a gear, and supports a bearing at least one end of the one shaft with a cover that can be attached to and detached from the case of the gear device. An elastic body that urges the one shaft in an axial direction and seals between the lid and the case between the lid and the bearing and the case, and the gear includes a worm and a worm. A wheel, wherein the one shaft is a worm shaft that supports the worm, and the gear device is used to drive a steering output shaft of an electric power steering device . When the gear shaft is urged in the axial direction by the elastic body with an elastic body interposed therebetween, the problem of sealing can be solved at the same time.

  In the electric power steering device of the present invention, the gear device is a worm reducer, and this worm reducer is used to drive the steering output shaft, so that the effect of the gear device is exhibited as an electric power steering device.

  Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1

  1A and 1B show an example of a gear device of the present invention, in which FIG. 1A is a cross-sectional view of an essential part thereof, FIG. 1B is a view taken along an arrow A thereof, and FIG. 2A is a bearing of FIG. The figure which shows only a hole part, (b) is sectional drawing which shows the cover of Fig.1 (a), (c) is sectional drawing which shows the elastic body of Fig.1 (a), (d) is attached to FIG. It is an expansion perspective view which shows a biasing means.

  The gear device 10 is a worm speed reducer that transmits power using a worm 1 as a gear and a worm wheel 3 that meshes with the worm 1. For example, the gear device 10 is a steering output shaft of an electric power steering device that assists steering of an automobile. It is used for rotation.

  The gear device 10 includes the worm 1, a worm shaft (one shaft) 2 provided with the worm 1, the worm wheel 3, and a steering output shaft (the other shaft) that supports the worm wheel 3 by synchronously rotating the worm wheel 3. 12.

  In addition to the above basic configuration, the gear device 10 supports a bearing 2a at least one end of the worm shaft 2 with a lid 6 that can be attached to and detached from the case 4 of the gear device 10, and the lid 6, the bearing 2a, and the case 4 The elastic body 7 is provided between the cover 6 and the case 4 so as to urge the worm shaft 2 in the axial direction between the cover 6 and the case 4.

  Further, in the gear device 10, the shaft center line of the steering output shaft 12 of the worm wheel 3 and the shaft center line of the worm shaft 2 are in a twisted position (relationship between staggered shafts), which is common to the worm speed reducer. It is a relationship.

  Corresponding to this relationship, the gear device 10 is configured such that the bearing 2a at one end of the worm shaft 2 is orthogonal to the direction of the steering output shaft 12 of the worm wheel 3 (inter-axis distance adjustment direction), Two urging means 8 for urging in a direction (advance angle adjusting direction) perpendicular to the radial plane of the worm wheel 3 are provided.

  Here, as can be seen from FIG. 1 (a), the lid 6 can be screwed with respect to the case 4 to advance and retract in the axial direction of the worm shaft 2. The lid 6, the case 4 and the worm shaft 2 can be moved back and forth. The elastic body 7 interposed between the first bearing 2a and the first bearing 2a urges the worm shaft 2 in the axial direction and at the same time seals the space between the case 4 and the lid 6 from the outside.

  FIG. 1B is a view as seen from the direction of arrow A in FIG. 1A, and shows a state in which the lid 6 and the elastic body 7 are removed.

  The elastic body 7 achieves the urging of the worm shaft 2 in the axial direction by utilizing the force from the lid 6, and is also interposed between the case 4 and the lid 6, and the case 4 and the lid 6. The seal between the two has also been achieved.

  That is, the gear device 10 is configured such that the elastic body 7 is interposed between the lid 6 of the gear device 10 and the worm shaft (gear shaft) 2 and the worm shaft (gear shaft) 2 is urged in the axial direction by the elastic body 7. At the same time, the sealing problem can be solved.

  In addition, this elastic body 7 also plays the role which suppresses backlash and eliminates an axial clearance by urging the worm shaft 2 in the axial direction.

  The structure of the characteristic part of the gear device 10 will be described in more detail with reference to FIG.

  FIG. 2A shows a portion for receiving the bearing 2a and the lid 6 of the case 4 except for the worm shaft 2 and the bearing 2a from the arrow view of FIG. 1B.

  As can be seen in FIG. 2 (a), in this portion of the case 4, a worm accommodating portion 4a for accommodating the worm 2 is seen in the innermost portion, and then in the front direction, a bearing accommodating hole 4b for accommodating the bearing 2a, A lid female screw hole 4f that is screw-engaged with the lid 6 is formed with a larger inner diameter than the bearing housing hole 4b.

  As shown in FIG. 1 (b), the inner diameter of the bearing receiving hole 4b is larger than the outer diameter of the bearing 2a, and is eccentric to the left by 45 degrees obliquely upward in this figure by the larger outer diameter. Therefore, the gap C between the inner periphery of the bearing receiving hole 4b and the outer periphery of the bearing 2a in the upper left part of the 45 ° diagonally is the largest, and the gap between both in the lower 45 ° diagonally lower part on the opposite side is zero. It has become.

  A gap CB is formed at a position corresponding to the biasing means 8 in the inter-axis distance adjustment direction, and a gap CL is formed at a position corresponding to the biasing means 8 in the advance angle adjustment direction.

  A step portion between the bearing housing hole 4b and the female screw hole for lid 4f is a seal surface 4e with which the elastic body 7 comes into surface contact. Two urging means accommodating recesses 4c and 4d for accommodating the two urging means 8 described above are provided at two locations on the outer periphery of the bearing accommodating hole 4b.

  The urging means accommodating recess 4c accommodates the urging means 8 in the inter-axis distance adjustment direction, and the urging means accommodation recess 4d accommodates the urging means 8 in the advance angle adjustment direction.

  The urging means 8 accommodated in the urging means accommodating recesses 4c and 4d does not protrude from the seal surface 4e, or when protruding, the elastic body 7 is provided with a relief portion. The sealing surface 4e is sealed including the peripheral edges of the biasing means accommodating recesses 4c and 4d.

  The lid 6 shown in FIG. 2 (b) has a disk shape in which a male screw portion 6b that engages with the female screw hole 4f for the lid of the case 4 is provided on the outer periphery, and an elastic body 7 is provided on one end face side in the radial direction. For example, a hexagonal turning recess 6c for turning and fixing the lid 6 is provided on the other end surface.

  The peripheral edge portion 6d of the elastic body fitting recess 6a of the lid 6 is in contact with the seal surface 4e of the case 4 and serves to tighten and fix the screw engagement between the male screw portion 6b and the female screw hole 4f for the lid. Yes.

  The elastic body 7 shown in FIG. 2 (c) is formed of natural rubber or rubber-based synthetic resin, has a disc ring shape as a whole, and fits into the elastic body fitting recess 6a of the lid 6 without gaps. A mating portion 7a, a fitting receiving portion 7b for fitting the bearing of the worm shaft 2 on the opposite side in the axial direction, and an end surface of the fitting receiving portion 7b, and a sealing surface that contacts the sealing surface 4e of the case 4 7c.

  The height of the sealing surface 7 c (the total thickness of the elastic body 7) is such that the peripheral edge 6 d of the lid 6 into which the elastic body 7 is fitted contacts the sealing surface 4 e of the case 4 when the peripheral edge 6 d contacts the sealing surface 4 e of the case 4. It is assumed that the elastic body is projected from the recessed portion 6a to such an extent that a sealing effect can be exhibited.

  The depth of the fitting receiving portion 7b is such that a necessary and sufficient urging force is applied to the bearing 2a of the worm 2 when the peripheral edge 6d of the lid 6 into which the elastic body 7 is fitted contacts the seal surface 4e of the case 4. The depth of it.

  The urging means 8 is a rectangular spring steel plate bent 90 degrees along a fold line parallel to one side thereof to form a “U” shape as a whole, one side of which is an open end through a pressing projection 8a. It has become. The pressing protrusion 8a is for avoiding the edge of the opening end from hitting the bearing 2a, and for pressing the bearing 2a at the central portion of the axial length of the bearing 2a.

  The urging means 8 generates an elastic urging force in the direction in which the distance between the opening portions of the “U” shape increases or decreases, and at this time, the pressing protrusion 8a contacts the bearing 2a. Then, the elastic biasing force is applied to the bearing 2a.

  By providing the case 4 having such a configuration, the lid 6 and the elastic body 7, according to the gear device 10, as described above, the peripheral edge 6 d of the lid 6 is simply the sealing surface 4 e of the case 4. It is possible to apply a necessary and sufficient urging force to the bearing 2a of the worm 2 and to seal the outside between the case 4 and the lid 6 simply by contacting and fixing.

  Note that the seal by the elastic body 7 achieves the sealing function of the gear device 10 for these because the influence of rainwater, sand dust, etc. is placed in a harsh environment, especially when installed as an electric power steering device outside the vehicle. The meaning of doing is important.

  The two urging means 8 urge the bearing 2a in the above-described direction, but the urging means 8 in the inter-axis distance adjustment direction is between the worm 1 and the worm wheel 3 within the gap CB. It is effective for adjusting the gap between the tooth surfaces (backlash) between them, and is effective for reducing the rattle noise.

  The urging means 8 in the advance angle adjustment direction is configured so that the advance angle of the worm is larger than the advance angle of the worm wheel in the range of the clearance CL. 8-8C), that is, without reducing the meshing efficiency between the two, to achieve good meshing between the two while high accuracy is not required for machining of the worm and the worm wheel, and assembly is easy (Paragraph 9 paragraphs [0063] to [0065]).

  Further, since the urging directions of the two urging means 8 are orthogonal to each other, there is a feature that one urging force does not affect the other urging force, and each can be adjusted independently. In addition, although the same code | symbol was attached | subjected to the two urging means 8 for convenience at this point, these may give different elastic urging | biasing force.

  In response to the urging force of these urging means 8, the elastic means 7 plays a role of buffering the urging force within the elastic range of the bearing 2a while being fixed to the lid 6 in the radial direction. Coordinated and moderate backlash adjustment and maintenance, thereby reducing rattle noise and achieving good meshing between the worm 1 and the worm wheel 3.

  In this example, the fitting portion 7a of the elastic means 7 is fitted in the elastic body fitting concave portion 6a of the lid 6, and the elastic means 7 is restrained in the radial direction, and the above effect is exhibited. The outer diameter may be fitted and restrained on the case side, and in that case, the same effect is exhibited.

Embodiment 2

  3 (a) and 3 (b) are cross-sectional views of main parts showing another example of the gear device of the present invention. Accordingly, the same parts as those already described may be denoted by the same reference numerals and redundant description may be omitted.

  The gear device (worm reducer) 10A shown in FIG. 3A has an elastic body 7A and a lid 6A that are not restrained in the radial direction relative to the gear device 10 shown in FIG. The difference is that only the urging force and the sealing function between the case 4 are generated.

  The axial length of the lid 6A is longer than that of the lid 6 of FIG. 1, and a part of the male screw portion 6e protrudes from the case 4, and a lock nut 6f is provided at the protruding portion. The lock nut 6f is fastened and fixed at a position where the forward / backward position of the lid 6A allows the urging force of the elastic body and the sealing function to be suitably exerted. This function is the same as that of the peripheral edge 6d of the lid 6 in FIG.

  Thus, according to the gear device 10A, the effect similar to that of the gear device 10 of FIG. 1, that is, the elastic body 7A is interposed between the cover 6A and the gear shaft 2 of the gear device 10A, thereby making the gear shaft 2 an elastic body. When urging in the axial direction with 7A, the effect that the problem of the seal can be solved at the same time can be exhibited.

  In the gear device 10B of FIG. 3B, the gears 1A and 3A that mesh with each other are helical gears as compared to the gear device 10 of FIG. 1, and the case 4A and the bearing 2b on one side of the one shaft 2A are also these. The difference is that it corresponds to the helical gear. Reference numeral 5 denotes the other axis.

  Further, the gear device 10B is not provided with an urging means. On the other hand, the lid 6B and the elastic body 7B are common to the gear device 10A of FIG. 3A in that they do not restrict each other in the radial direction, and the male screw portion 6g and the lock nut 6h of the lid 6B are also provided with this gear device. The same functions and effects as those of the 10A male thread portion 6e and the lock nut 6f are exhibited.

  In the case of a helical gear, an axial force is generated. In this case, a biasing force for adjusting the axial force is applied, and at the same time, a gear device 10B according to the present invention that achieves a seal between the lid and the case. Is valid.

Embodiment 3

  FIG. 4A is a diagram conceptually showing the overall configuration of an electric power steering apparatus using the gear device of FIG. 1, and FIG. 4B is a sectional view of the main part of FIG.

  The electric power steering device 20 includes the worm reduction gear (gear device) 10, the steering input shaft 11, the steering output shaft 12, the torsion bar 13, the steering rack 14, the steering housing 15, and the torque sensor 16 shown in FIG. 1. Reference numeral 9 denotes an electric motor that drives the worm shaft 2 to rotate.

  A steering wheel H for steering operation is connected to a steering input shaft 11, the steering input shaft 11 and the steering output shaft 12 are connected via a torsion bar 13, and torque generated in the torsion bar 13 during steering is measured by a torque sensor. 16, the steering output shaft 12 that rotates together with the worm wheel 3 is rotationally driven by the worm speed reducer 10.

  Since the steering output shaft 12 is provided with a steering pinion 12a that meshes with the steering rack 14, the steering rack 14 slides, and accompanying this sliding, the steering assist of the wheels T of an automobile or the like is performed.

  The electric power steering device 20 assists the steering force as described above. At this time, the worm speed reducer 10 is used to drive the steering output shaft 12.

  Therefore, this electric power steering apparatus 20 can exhibit the effect of the worm speed reducer 10 as an electric power steering apparatus.

  In addition, the electric power steering apparatus can use the worm speed reducer 10A instead of the worm speed reducer 10, and in that case, the effect of the worm speed reducer 10A can be exhibited as the electric power steering apparatus.

  The gear device and the electric power steering device of the present invention are not limited to the above-described embodiments, and various modifications and combinations are possible within the scope described in the claims and the scope of the embodiments. These modifications and combinations are also included in the scope of the right.

  For example, a lid 6A that is fastened and fixed by a lock nut 6f in FIG. 3A may be used instead of the lid 6 in FIG.

  The gear device and the electric power steering device according to the present invention also have a sealing problem when the elastic body is interposed between the lid of the gear device and the gear shaft and the gear shaft is urged in the axial direction by the elastic body. It can be used in industrial fields that are required to be solved.

An example of the gear apparatus of this invention is shown, (a) is the principal part sectional drawing, (b) is the A arrow directional view. (A) is a figure which shows only the bearing hole part of FIG.1 (b), (b) is sectional drawing which shows the lid | cover of FIG.1 (a), (c) is sectional drawing which shows the elastic body of FIG.1 (a). , (D) is an enlarged perspective view showing the biasing means of FIG. 1 (d). (A), (b) is principal part sectional drawing which shows the other examples of the gear apparatus of this invention. (A) is a figure which shows notionally the whole structure of the electric power steering apparatus using the gear apparatus of FIG. 1, (b) is principal part sectional drawing of (a).

Explanation of symbols

1 Worm (gear)
1A gear
2 One shaft (worm shaft)
2A One shaft 2a Bearing 2b Bearing 3 Worm wheel (gear)
3A Gear 4, 4A Case 5 Other shaft 6-6B Lid 7-7B Elastic body 10, 10A Worm speed reducer (gear device)
12 Other shaft (steering output shaft)
20 Electric power steering system

Claims (4)

A gear device that transmits power from one shaft to the other using a gear,
The bearing of at least one end of the one shaft is supported by a lid that can be attached to and detached from the case of the gear device,
Between the lid and the bearing and the case, an elastic body that urges the one shaft in the axial direction and seals between the lid and the case ,
The gear is a worm and a worm wheel, the one shaft is a worm shaft that supports the worm, and the gear device is used to drive a steering output shaft of an electric power steering device. Gear device. The gear device according to claim 1, wherein the elastic body elastically supports the worm shaft in an axial direction by elastically supporting a bearing at one end of the worm shaft. The gear device according to claim 1 or 2, wherein the elastic body elastically supports the worm shaft in a radial direction by receiving a bearing at one end of the worm shaft. An electric power steering device, wherein the gear device according to any one of claims 1 to 3 is used for driving a steering output shaft.

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