Motorized reducer

Abstract

To suppress cost increase and furthermore to enable effective prevention of grease leakage due to misalignment of an oil seal.SOLUTION: A reduction gear 1 with a motor is provided in which: a motor case 4 housing a motor 5 is fixed to a reduction gear case 2 housing a speed reduction unit 3 through a cylindrical coupling portion 6; a distal end of a rotary shaft 22 of the motor 5 protrudes into the reduction gear case 2 penetrating through the coupling portion 6; a ball bearing 30 supporting the rotary shaft 22; and an oil seal 34 sealing between the coupling portion 6 and the rotary shaft 22 on the front side of the ball bearing 30 are arranged in the coupling portion 6. A collar 35 preventing the oil seal 34 from abutting on an inner ring 31 of the ball bearing 30 is provided in the inner circumferential surface of the coupling portion 6 and between the ball bearing 30 and the oil seal 34.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a motorized reducer having a motor integrally attached thereto. [Background technology]

[0002] A motor-equipped reducer is constructed by attaching a motor case that houses a motor to a reducer case that houses a reduction unit including an output shaft and gears. The rotating shaft of the motor passes through a connecting portion provided on one of the reducer case and the motor case, protruding into the reducer case and meshing with the gear of the reduction unit. As disclosed in Patent Document 1, the rotating shaft is supported by a ball bearing within the connecting portion. An oil seal that seals the gap between the connecting portion and the rotating shaft is disposed adjacent to the ball bearing within the connecting portion, closer to the reducer case. This oil seal is used to prevent grease from inside the reducer case from seeping into the motor case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3100264 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned conventional motor-equipped reducer, if the internal pressure of the reducer case increases due to a rise in temperature or the like, the oil seal may be pressed toward the ball bearing and come into contact with the ball bearing. Because the inner ring of the ball bearing rotates with the rotating shaft, contact between the oil seal and the inner ring can cause damage, reducing sealing performance and causing grease to leak into the motor case. While it is possible to provide a retaining ring for the oil seal on the rotating shaft, this would require machining a groove for the retaining ring into the rotating shaft, leading to increased costs.

[0005] Therefore, an object of the present disclosure is to provide a motor-equipped reducer that can effectively prevent grease leakage due to misalignment of the oil seal while suppressing increases in cost. [Means for solving the problem]

[0006] In order to achieve the above object, the present disclosure provides a reducer case that houses a speed reducer unit, and a motor case that houses a motor is fixed to the reducer case via a cylindrical connecting part, and a tip of a rotating shaft of the motor penetrates the connecting part and protrudes into the reducer case, Within the connecting portion, a rolling bearing that supports the rotating shaft and an oil seal that seals between the connecting portion and the rotating shaft are arranged on the reducer case side of the rolling bearing. A contact prevention member is provided on the inner peripheral surface of the connecting portion between the rolling bearing and the oil seal to prevent the oil seal from contacting the inner ring of the rolling bearing. A motor-equipped reducer comprising: The contact prevention member is a ring-shaped collar whose inner diameter is smaller than the outer diameter of the oil seal and the outer diameter of the inner ring, and a ring-shaped notch whose outer diameter is larger than the outer diameter of the inner ring is formed on the inner peripheral side of the end face of the collar on the rolling bearing side. It is characterized by: Another aspect of the present disclosure is the above-mentioned configuration, color is characterized in that it abuts against the oil seal. Another aspect of the present disclosure is the above-mentioned configuration, color is characterized in that it abuts against the outer ring of the rolling bearing. [Effects of the Invention]

[0007] According to the present disclosure, the contact prevention member prevents the oil seal from contacting the inner ring of the rolling bearing, thereby effectively preventing grease leakage due to misalignment of the oil seal while suppressing increases in cost. In particular, since the contact prevention member is a ring-shaped collar whose inner diameter is smaller than the outer diameter of the oil seal, it can reliably contact the oil seal. In addition, the inner diameter of the collar is smaller than the outer diameter of the inner ring, and a ring-shaped notch whose outer diameter is larger than the outer diameter of the inner ring is formed on the inner side of the end face of the collar facing the rolling bearing.This allows the inner diameter of the collar to be small while avoiding contact with the inner ring, and ensures a large contact area with the oil seal. According to another aspect of the present disclosure, in addition to the above effects, color Since the oil seal is in contact with the oil seal, the effect of preventing the oil seal from slipping is improved. According to another aspect of the present disclosure, in addition to the above effects, color is in contact with the outer ring of the rolling bearing, color This makes it easier to position the device. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a vertical cross-sectional view of a motorized reducer. [Figure 2] FIG. 10 is an enlarged vertical cross-sectional view of a connecting portion showing a modified example of a motor-equipped reducer. [Figure 3] FIG. 10 is an enlarged vertical cross-sectional view of a connecting portion showing another modified example of the motor-equipped reducer. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. 1 is a vertical cross-sectional view showing an example of a motorized reducer, and for convenience, the left side of FIG. 1 will be referred to as the front. The motor-equipped reducer (hereinafter simply referred to as "reducer") 1 is constructed by connecting a square box-shaped reducer case 2 that houses a reduction unit 3 to a cylindrical motor case 4 that houses a motor 5 via a connecting part 6. The connecting part 6 protrudes rearward from the rear surface of the reducer case 2 and is cylindrical with a through-hole 7 that passes through from front to back. The reduction gear unit 3 includes an input pinion 10 , an intermediate gear set 11 , and an output gear set 12 . The input pinion 10 passes through the connecting portion 6 and protrudes into the reducer case 2 . The intermediate gear set 11 includes an intermediate shaft 13 supported in a direction perpendicular to the input pinion 10, a large-diameter gear 14 integrally coupled to the intermediate shaft 13, and a pinion 15 formed on the intermediate shaft 13 coaxially with the gear 14 and having a smaller diameter than the gear 14. The input pinion 10 is in mesh with the gear 14. The output gear set 12 includes a hollow output shaft 16 that is supported perpendicular to the input pinion 10 and has both ends protruding from the reducer case 2, and a large-diameter output gear 17 that is integrally connected to the output shaft 16 and meshes with the pinion 15.

[0010] The motor 5 has a stator 20 fixed inside the motor case 4, and a rotor 21 that penetrates the stator 20 and has a rotating shaft 22 at its axis. The rear portion of the rotating shaft 22 is supported via a ball bearing 23 at the rear portion of the motor case 4. A ring-shaped receiving portion 24 that fits onto the rear end of the connecting portion 6 is provided at the front end of the motor case 4. The receiving portion 24 is attached to the rear end of the connecting portion 6 with a plurality of bolts 25, 25.... The front portion of the rotating shaft 22 coaxially penetrates the connecting portion 6, and the input pinion 10 is provided coaxially and integrally with the front end of the rotating shaft 22. The through-holes 7 of the connecting portion 6 are, from the front, a small diameter hole 26, a medium diameter hole 27, and a large diameter hole 28, and gradually widen toward the rear. A ball bearing 30 that supports the front portion of the rotating shaft 22 is provided within the large diameter hole 28. The ball bearing 30 includes an inner ring 31 that is integral with the rotating shaft 22, an outer ring 32 that is held in the large diameter hole 28, and a plurality of balls 33, 33... that are arranged between the inner ring 31 and the outer ring 32. An oil seal 34 is provided in the medium diameter hole 27 in front of the ball bearing 30 to seal between the rotary shaft 22 and the connecting portion 6 .

[0011] A ring-shaped collar 35 is provided inside the large diameter hole 28, between the ball bearing 30 and the oil seal 34. The front surface of the collar 35 abuts against a step 36 between the medium diameter hole 27 and the large diameter hole 28. The rear surface of the collar 35 abuts against the outer ring 32 of the ball bearing 30. The outer ring 32 abuts against the receiving portion 24 of the motor case 4, restricting rearward movement. Thus, the collar 35 is positioned in the front-to-rear direction between the step 36 and the outer ring 32. The inner diameter of the collar 35 is set smaller than the outer diameter of the oil seal 34 , and the front surface of the collar 35 abuts against the rear surface of the oil seal 34 . The inner diameter of the collar 35 is set to be larger than the outer diameter of the inner ring 31 of the ball bearing 30 .

[0012] In the reducer 1 configured as described above, when assembling the motor case 4 to the connecting portion 6, the front portion of the rotating shaft 22, to which the oil seal 34, collar 35, and ball bearing 30 are attached in this order from the front, is inserted into the through hole 7 from the rear, and the oil seal 34 is fitted into the medium diameter hole 27, and the collar 35 and ball bearing 30 are fitted into the large diameter hole 28. When the receiving portion 24 is connected to the connecting portion 6 with the bolt 25, the collar 35 is interposed between the oil seal 34 and the ball bearing 30 as shown in Figure 1. In this state, the collar 35 does not abut against the inner ring 31, and the oil seal 34 does not come into contact with the inner ring 31 either. In this way, the collar 35 can be easily assembled by simply inserting it into the large diameter hole 28 together with the ball bearing 30. This eliminates the need to machine a groove for a retaining ring on the rotary shaft 22, thereby preventing an increase in costs.

[0013] Even when the motor 5 is driven using this reducer 1, the collar 35 does not interfere with the inner ring 31, and therefore the rotation of the rotary shaft 22 is not hindered. When the internal pressure of the reducer case 2 increases due to a rise in temperature or the like caused by use of the reducer 1, the oil seal 34 is pressed backward (towards the motor 5) within the connecting portion 6. However, because the rearward movement of the oil seal 34 is restricted by the collar 35, there is no risk of the oil seal 34 moving backward and coming into contact with the inner ring 31.

[0014] Thus, according to the above-described form of reducer 1, the motor case 4 that houses the motor 5 is fixed to the reducer case 2 that houses the reduction section 3 via a cylindrical connecting section 6, and the tip of the rotating shaft 22 of the motor 5 passes through the connecting section 6 and protrudes into the reducer case 2, and a ball bearing 30 (rolling bearing) that supports the rotating shaft 22 and an oil seal 34 that seals between the connecting section 6 and the rotating shaft 22 forward of the ball bearing 30 (towards the reducer case 2) are arranged within the connecting section 6, and a collar 35 (contact prevention member) that prevents the oil seal 34 from contacting the inner ring 31 of the ball bearing 30 is provided on the inner surface of the connecting section 6 between the ball bearing 30 and the oil seal 34. This configuration makes it possible to effectively prevent grease leakage due to misalignment of the oil seal 34 while suppressing increases in costs.

[0015] In particular, since the collar 35 abuts against the oil seal 34, the effect of preventing the oil seal 34 from slipping is improved. Since the collar 35 abuts against the outer ring 32 of the ball bearing 30, the positioning of the collar 35 is easy. The contact prevention member employs a ring-shaped collar 35 whose inner diameter is smaller than the outer diameter of the oil seal 34, so that the contact with the oil seal 34 can be ensured. Since the inner diameter of the collar 35 is larger than the outer diameter of the inner ring 31, the collar 35 can be reliably prevented from coming into contact with the inner ring 31.

[0016] The collar is not limited to the above-described structure in which the thickness between the front and rear ends does not change in the radial direction. 2 shows a connecting portion 6 of the reducer 1 having a different collar structure. The collar 35A here has an inner diameter smaller than the outer diameter of the oil seal 34 and the outer diameter of the inner ring 31. However, on the inner peripheral side of the rear surface of collar 35A, a ring-shaped cutout 37 is formed with the same thickness in the radial direction and has an outer diameter larger than that of inner ring 31. Therefore, the rear surface of collar 35A does not come into contact with inner ring 31. In this reducer 1 as well, the collar 35A, which does not abut against the inner ring 31, keeps the oil seal 34 out of contact with the inner ring 31. This makes it possible to effectively prevent grease leakage due to misalignment of the oil seal 34 while suppressing increases in costs. In particular, here, a ring-shaped cutout 37 whose outer diameter is larger than the outer diameter of the inner ring 31 is formed on the inner peripheral side of the rear surface of the collar 35A, so that the inner diameter of the collar 35A can be made small while avoiding contact with the inner ring 31, ensuring a large contact area with the oil seal 34. However, the cutout portion is not limited to a structure having the same thickness in the radial direction, and may be a tapered cutout portion 38 that gradually becomes thicker toward the front as it moves radially from an outer diameter that is larger than the outer diameter of the inner ring 31 toward the center, as in the collar 35B of the reducer 1 shown in Figure 3.

[0017] Alternatively, the contact prevention member is not limited to a collar, and may be a plurality of ring-shaped shim plates or washers stacked in the axial direction, each having an inner diameter smaller than the outer diameter of the oil seal. In this case, the inner diameters of all shim plates, etc. may be larger than the outer diameter of the inner ring, or only one or more shim plates, etc. on the inner ring side may have an inner diameter larger than the outer diameter of the inner ring. The contact prevention member may be out of contact with either or both of the oil seal and the outer ring. The rolling bearing is not limited to a ball bearing, but may be one using rollers. The reduction section is not limited to the above configuration either. For example, it may have two or more intermediate gear sets, or may have no intermediate gear set and the input pinion meshes with the output gear of the output gear set. The connecting portion may be provided integrally with the motor case rather than the reducer case, or the connecting portion may be formed by butting together cylindrical portions provided on the reducer case and the motor case. Separate connecting portions may be connected to the reducer case and the motor case, respectively. [Explanation of symbols]

[0018] 1··Reduction gear with motor, 2··Reduction gear case, 3··Reduction section, 4··Motor case, 5··Motor, 6··Coupling section, 10··Input pinion, 11··Intermediate gear set, 12··Output gear set, 16··Output shaft, 22··Rotating shaft, 23, 30··Ball bearing, 24··Receiving section, 28··Large diameter hole, 31··Inner ring, 32··Outer ring, 33··Ball, 34··Oil seal, 35, 35A, 35B··Collar, 36··Step section, 37, 38··Notched section.

Claims

1. a motor case that houses a motor is fixed to a reducer case that houses a reduction unit via a cylindrical connecting part, and a tip of a rotation shaft of the motor penetrates the connecting part and protrudes into the reducer case; a rolling bearing that supports the rotating shaft and an oil seal that seals between the connecting portion and the rotating shaft on the reducer case side of the rolling bearing are disposed within the connecting portion, and a contact prevention member that prevents the oil seal from contacting an inner ring of the rolling bearing is provided on an inner circumferential surface of the connecting portion between the rolling bearing and the oil seal, a reduction gear with a motor, characterized in that the contact prevention member is a ring-shaped collar whose inner diameter is smaller than the outer diameter of the oil seal and the outer diameter of the inner ring, and a ring-shaped notch whose outer diameter is larger than the outer diameter of the inner ring is formed on the inner side of the end face of the collar facing the rolling bearing.

2. 2. The motor-equipped reducer according to claim 1, wherein the collar abuts against the oil seal.

3. 3. The motor-equipped reducer according to claim 1, wherein the collar abuts against an outer ring of the rolling bearing.

Images