JP2022093033A - Speed reducer - Google Patents

Abstract

To improve sealability between a housing and a cover of a speed reducer.SOLUTION: A speed reducer 100 includes: a housing 11 having an opening 10; a cover 12 which seals the opening 10 of the housing 11; and a seal member 13 which is compressively provided between the housing 11 and the cover 12 and seals a space therebetween. The cover 12 has a press-fitting part 12c which is provided in an annular form on an outer peripheral surface 12f and press-fitted in an inner peripheral surface 11b of the housing 11.SELECTED DRAWING: Figure 2

Description

The present invention relates to a speed reducer.

In the speed reducer described in Patent Document 1, a cover is fastened to a housing accommodating the speed reducer by a plurality of bolts.

Japanese Unexamined Patent Publication No. 2017-227227

In such a speed reducer, a sealing member such as an O-ring is provided to seal the housing and the cover. However, it may not be possible to obtain a high sealing property between the housing and the cover only with the sealing member.

The present invention has been made in view of the above problems, and an object of the present invention is to improve the sealing property between the housing and the cover of the speed reducer.

The present invention is a speed reducer, which is a housing having an opening, a cover that seals the opening of the housing, and a sealing member that is compressed and provided between the housing and the cover and seals between the two. The cover is characterized by having a press-fitting portion provided in an annular shape on the outer peripheral surface and press-fitted into the inner peripheral surface of the housing.

In the present invention, since the press-fitting portion is press-fitted into the inner peripheral surface of the housing, the press-fitting portion seals the space between the housing and the cover. Also sealed by. Therefore, the sealing property between the housing and the cover can be improved.

The present invention is characterized in that the press-fitting portion is a protrusion provided so as to project from the outer peripheral surface of the cover.

In the present invention, since the press-fitting portion is a protrusion, the press-fitting portion can be press-fitted into the inner peripheral surface of the housing with a small force. Therefore, the speed reducer can be easily assembled.

The present invention is characterized in that the seal member is provided between the outer peripheral surface of the cover and the inner peripheral surface of the housing, and the press-fitting portion is provided on the opening side of the seal member.

In the present invention, the press-fitting portion of the cover is provided on the opening side of the housing. This prevents the sealing member from coming into contact with foreign matter and deteriorating. Therefore, the sealing property between the housing and the cover can be improved.

The present invention is characterized in that the cover is fixed to the housing only by the press-fitting portion.

In the present invention, the press-fitting portion of the cover seals between the housing and the cover and fixes the housing and the cover. Therefore, it is not necessary to provide a fastening member for fixing the housing and the cover. Therefore, the number of parts of the speed reducer can be reduced.

According to the present invention, the sealing property between the housing and the cover of the speed reducer can be improved.

It is a partial cross-sectional view of the speed reducer which concerns on embodiment of this invention. It is an enlarged sectional view of the fixing part of a housing and a cover. It is an enlarged sectional view of the cover which concerns on a modification. It is an enlarged sectional view corresponding to FIG. 3 of the cover which concerns on a modification. It is an enlarged sectional view corresponding to FIG. 2 of the fixed part of the housing and the cover which concerns on a modification. It is an enlarged sectional view corresponding to FIG. 2 of the fixed part of the housing and the cover which concerns on a modification.

The speed reducer 100 according to the embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the case where the speed reducer 100 is used for the electric power steering device will be described.

The electric power steering device decelerates the driving force of the electric motor (not shown) by the speed reducer 100 and applies it to the rack shaft (not shown) as a rotational torque that assists the steering of the steering wheel by the driver.

As shown in FIG. 1, the speed reducer 100 includes a worm shaft 1 to which a driving force from an electric motor is input, a worm wheel 2 that meshes with the worm shaft 1, a pinion shaft 3 that rotates integrally with the worm wheel 2, and a pinion shaft 3. A pinion 4 formed on the pinion shaft 3 and meshing with the rack shaft, and bearings 5 and 6 for rotatably supporting the pinion shaft 3 are provided.

The driving force from the electric motor is transmitted to the rack shaft through the worm shaft 1, the worm wheel 2, the pinion shaft 3, and the pinion 4, and acts to assist the steering force of the driver.

Further, the speed reducer 100 is provided by compression between the housing 11 having the opening 10, the cover 12 for sealing the opening 10 of the housing 11, and the housing 11 and the cover 12, and seals between the two. A seal member 13 is provided. The housing 11 and the cover 12 are fixed by a plurality of bolts 14 as fastening members. A fastening hole 11a to which the bolt 14 is fastened is provided on the end surface of the housing 11. The housing 11 is made of a metal such as aluminum.

In the present embodiment, the opening 10 of the housing 11 is circular, and the cover 12 is formed in a disk shape so as to seal the opening 10. The cover 12 is made of, for example, resin. The cover 12 may be made of metal.

As shown in FIGS. 1 and 2, the cover 12 includes a main body portion 12a inserted into the opening 10 of the housing 11 and an annular flange portion 12b formed so as to project radially from the outer peripheral surface 12f of the main body portion 12a. Have. The outer peripheral surface 12f of the main body portion 12a is provided with an annular press-fitting portion 12c (see FIG. 2) that is press-fitted into the inner peripheral surface 11b of the housing 11 and an annular accommodating groove 12d in which the seal member 13 is accommodated. .. An insertion hole 12e through which the bolt 14 is inserted is formed in the flange portion 12b. A metal collar 15 (see FIG. 2) is inserted into the insertion hole 12e.

The main body portion 12a is formed in a disk shape having an outer diameter substantially the same as the inner diameter of the inner peripheral surface 11b of the housing 11. The press-fitting portion 12c is a protrusion provided so as to project from the outer peripheral surface 12f of the main body portion 12a, and has a semicircular cross section in the present embodiment. The press-fitting portion 12c has a tightening allowance with respect to the inner peripheral surface 11b of the housing 11. Therefore, when the main body portion 12a is inserted into the opening portion 10 of the housing 11, the press-fitting portion 12c is radially crushed by the inner peripheral surface 11b of the housing 11 and is in close contact with the inner peripheral surface 11b. The flange portion 12b is pressed and fixed to the end face of the housing 11 by the fastening force of the bolt 14.

The seal member 13 is an annular elastic member such as an O-ring, and is provided by being compressed in the radial direction between the inner peripheral surface 11b of the housing 11 and the accommodating groove 12d of the cover 12. That is, the accommodating groove 12d is formed at a depth at which the sealing member 13 is exposed while the sealing member 13 is accommodated.

In the speed reducer 100, the press-fitting portion 12c of the cover 12 is press-fitted into the inner peripheral surface 11b of the housing 11, so that the press-fitting portion 12c is in close contact with the inner peripheral surface 11b, and the press-fitting portion 12c between the housing 11 and the cover 12. Be sealed. Therefore, the space between the housing 11 and the cover 12 is sealed not only by the sealing member 13 but also by the press-fitting portion 12c of the cover 12. Therefore, the sealing property between the housing 11 and the cover 12 can be improved.

Further, the press-fitting portion 12c is press-fitted into the inner peripheral surface 11b of the housing 11, so that a force acts in the radial direction. That is, a constant force acts on the press-fitting portion 12c regardless of the position in the circumferential direction. Therefore, the press-fitting portion 12c is uniformly crushed over the entire circumference, and the press-fitting portion 12c and the inner peripheral surface 11b are in close contact with each other. Therefore, the sealing property between the housing 11 and the cover 12 can be further improved.

Therefore, for example, even when salt water is sprayed on the speed reducer 100 in a quality test or the like, the sealing property between the housing 11 and the cover 12 is high, so that the salt water invades into the housing 11 and is made of aluminum. It is possible to prevent the 11 from corroding.

Further, the press-fitting portion 12c is provided on the opening 10 side of the sealing member 13. That is, foreign matter or liquid that tends to enter the housing 11 from between the housing 11 and the cover 12 comes into contact with the press-fitting portion 12c before the sealing member 13. This prevents the seal member 13 from coming into contact with foreign matter or liquid and deteriorating. Therefore, the sealing property between the housing 11 and the cover 12 can be improved.

Further, since the press-fitting portion 12c is provided as a part of the cover 12, the sealing property between the housing 11 and the cover 12 can be improved without providing another member in the speed reducer 100. Further, by molding the press-fitting portion 12c together with the injection molding of the cover 12, the cover 12 can be manufactured without increasing the manufacturing cost from the conventional cover without the press-fitting portion 12c.

According to the above embodiment, the following actions and effects are exhibited.

In the speed reducer 100, since the press-fitting portion 12c of the cover 12 is press-fitted into the inner peripheral surface 11b of the housing 11, the space between the housing 11 and the cover 12 is sealed by the press-fitting portion 12c of the cover 12 in addition to the sealing member 13. Will be done. Therefore, the sealing property between the housing 11 and the cover 12 can be improved.

Since the press-fitting portion 12c is press-fitted into the inner peripheral surface 11b of the housing 11, the press-fitting portion 12c is uniformly crushed over the entire circumference, and the press-fitting portion 12c and the inner peripheral surface 11b are in close contact with each other. Therefore, the sealing property between the housing 11 and the cover 12 can be improved.

Since the press-fitting portion 12c is provided as a part of the cover 12, the sealing property between the housing 11 and the cover 12 can be improved without providing a separate member for the speed reducer 100. Further, by molding the press-fitting portion 12c together with the injection molding of the cover 12, the cover 12 can be manufactured without increasing the manufacturing cost from the conventional cover without the press-fitting portion 12c.

Since the seal member 13 is provided between the outer peripheral surface 12f of the cover 12 and the inner peripheral surface 11b of the housing 11, and the press-fitting portion 12c is provided on the opening 10 side of the seal member 13, the seal member 13 is a foreign substance. It is suppressed from coming into contact with and deteriorating. Therefore, the sealing property between the housing 11 and the cover 12 can be improved.

Next, a modification of the present embodiment will be described.

<Modification 1>
In the above embodiment, the press-fitting portion 12c is a protrusion having a semicircular cross section, and the number of protrusions is one. However, the number and shape of the press-fitting portions 12c may be such that there is a tightening allowance with respect to the inner diameter of the opening 10 of the housing 11. For example, as shown in FIG. 3, two or a plurality of protrusions may be provided apart from each other in the axial direction. By increasing the number of protrusions, the number of places to seal between the housing 11 and the cover 12 increases, and the sealing property between the housing 11 and the cover 12 can be improved. Further, the shape of the protrusions may be triangular in cross section, and when the number of protrusions is plurality, both protrusions having a semicircular cross section and protrusions having a triangular cross section may coexist. good.

Further, as shown in FIG. 4, the press-fitting portion 12c may be a tapered surface formed on a part or the whole of the outer peripheral surface 12f of the main body portion 12a so as to be inclined with respect to the inner peripheral surface 11b of the housing 11. good. In FIG. 4, the inclination of the press-fitting portion 12c is exaggerated. Even with these configurations, the space between the housing 11 and the cover 12 is sealed not only by the sealing member 13 but also by the press-fitting portion 12c of the cover 12, so that the sealing property between the housing 11 and the cover 12 is improved. Can be made to. However, in the configuration in which the press-fitting portion 12c is a tapered surface inclined with respect to the inner peripheral surface 11b of the housing 11, the contact area between the press-fitting portion 12c and the inner peripheral surface 11b of the housing 11 is large. On the other hand, in the above-described embodiment shown in FIGS. 1 and 2, since the press-fitting portion 12c is a protrusion, the press-fitting portion 12c and the inner peripheral surface 11b of the housing 11 are compared with the configuration in which the press-fitting portion 12c is a tapered surface. The contact area with is small. Therefore, the press-fitting portion 12c can be press-fitted into the inner peripheral surface 11b of the housing 11 with a small force. Therefore, the speed reducer 100 can be easily assembled. Further, since the force for press-fitting the press-fitting portion 12c is small, the device that performs the step in the manufacture of the speed reducer 100 does not require a large force for press-fitting the press-fitting portion 12c. Therefore, since the capacity of the device can be reduced, the manufacturing cost of the speed reducer 100 can be reduced. The press-fitting portion 12c may be formed on an outer peripheral surface 12f which is a tapered surface inclined with respect to the inner peripheral surface 11b of the housing 11.

<Modification 2>
In the above embodiment, the seal member 13 is provided by being compressed in the radial direction between the inner peripheral surface 11b of the housing 11 and the accommodating groove 12d of the cover 12. However, as shown in FIG. 5, the seal member 13 may be provided between the housing 11 and the cover 12 by compressing in the axial direction. Specifically, an accommodating groove 11e for accommodating the seal member 13 is provided on the end surface of the housing 11, and the seal member 13 is provided by being compressed in the axial direction between the accommodating groove 11e and the flange portion 12b. However, in this configuration, the seal member 13 is axially compressed by the fastening force of each bolt 14. Therefore, due to the arrangement of the bolts 14 and the difference in the fastening force of each bolt 14, the force acting on the seal member 13 in the axial direction differs depending on the position in the circumferential direction of the seal member 13, and the seal member 13 is axially over the entire circumference. It is not uniformly compressed, and the sealing property of the sealing member 13 may become unstable. On the other hand, in the above embodiment shown in FIGS. 1 and 2, since the seal member 13 is provided by compressing in the radial direction between the inner peripheral surface 11b of the housing 11 and the accommodating groove 12d of the cover 12, the bolt 14 is provided. The sealing member 13 is uniformly compressed in the radial direction over the entire circumference regardless of the arrangement of the bolts and the difference in the fastening force of each bolt 14, and the sealing property of the sealing member 13 is stabilized.

<Modification 3>
In the above embodiment, the housing 11 and the cover 12 are fixed by bolts 14. However, as shown in FIG. 6, the bolt 14 may not be provided. That is, the cover 12 may be fixed to the housing 11 only by the press-fitting portion 12c. In this case, the press-fitting portion 12c of the cover 12 seals between the housing 11 and the cover 12, and fixes the housing 11 and the cover 12. Therefore, it is not necessary to provide a fastening member such as a bolt 14 for fixing the housing 11 and the cover 12, and the number of parts of the speed reducer 100 can be reduced.

The configuration, operation, and effect of the embodiment of the present invention configured as described above will be collectively described.

The speed reducer 100 is a sealing member provided by compression between the housing 11 having the opening 10, the cover 12 for sealing the opening 10 of the housing 11, and the housing 11 and the cover 12, and sealing between the two. The cover 12 has a press-fitting portion 12c provided in an annular shape on the outer peripheral surface 12f and press-fitted into the inner peripheral surface 11b of the housing 11.

In this configuration, since the press-fitting portion 12c is press-fitted into the inner peripheral surface 11b of the housing 11, the press-fitting portion 12c seals between the housing 11 and the cover 12, so that the space between the housing 11 and the cover 12 is sealed. In addition to the member 13, it is also sealed by the press-fitting portion 12c of the cover 12. Therefore, the sealing property between the housing 11 and the cover 12 can be improved.

Further, the press-fitting portion 12c is a protrusion provided so as to project from the outer peripheral surface 12f of the cover 12.

In this configuration, since the press-fitting portion 12c is a protrusion, the press-fitting portion 12c can be press-fitted into the inner peripheral surface 11b of the housing 11 with a small force. Therefore, the speed reducer 100 can be easily assembled.

Further, the seal member 13 is provided between the outer peripheral surface 12f of the cover 12 and the inner peripheral surface 11b of the housing 11, and the press-fitting portion 12c is provided on the opening 10 side of the seal member 13.

In this configuration, the press-fitting portion 12c of the cover 12 is provided on the opening 10 side of the housing 11. As a result, it is possible to prevent the seal member 13 from coming into contact with foreign matter and deteriorating. Therefore, the sealing property between the housing 11 and the cover 12 can be improved.

Further, the cover 12 is fixed to the housing 11 only by the press-fitting portion 12c.

In this configuration, the press-fitting portion 12c of the cover 12 seals between the housing 11 and the cover 12, and fixes the housing 11 and the cover 12. Therefore, it is not necessary to provide a fastening member for fixing the housing 11 and the cover 12. Therefore, the number of parts of the speed reducer 100 can be reduced.

Although the embodiments of the present invention have been described above, the above-described embodiments show only a part of the application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above-described embodiments. do not have.

In the above embodiment, an example of applying the present invention to the speed reducer 100 of the electric power steering device has been described, but the present invention can be applied to the speed reducers of various machines such as conveyors, winches, machine tools, and construction machines. can.

10 ... opening, 11 ... housing, 11b ... inner peripheral surface, 12 ... cover, 12c ... press-fitting part (projection, tapered surface), 12f ... outer peripheral surface, 13 ...・ Seal member, 100 ・ ・ ・ Reducer

Claims (4)

It ’s a reducer,
A housing with an opening and
A cover that seals the opening of the housing and
A seal member provided between the housing and the cover by compression and sealing between the two is provided.
The cover is a speed reducer provided in an annular shape on an outer peripheral surface and having a press-fitting portion to be press-fitted into the inner peripheral surface of the housing. The speed reducer according to claim 1.
The speed reducer is characterized in that the press-fitting portion is a protrusion provided so as to project from the outer peripheral surface of the cover. The speed reducer according to claim 1 or 2.
The sealing member is provided between the outer peripheral surface of the cover and the inner peripheral surface of the housing.
The speed reducer is characterized in that the press-fitting portion is provided on the opening side of the sealing member. The speed reducer according to any one of claims 1 to 3.
A speed reducer characterized in that the cover is fixed to the housing only by the press-fitting portion.

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