JP7460105B2 - Bearing structure and assembly method thereof - Google Patents

Description

The present invention relates to a bearing structure with relatively rotating members and an assembly method thereof, and in particular to a bearing structure that can apply an appropriate preload to the bearing and an assembly method thereof.

BACKGROUND ART Conventionally, a bearing included in a rotation detector described in Cited Document 1 is held with a predetermined pressurized load applied thereto. The pressurized load is not directly applied to the bearing, but is managed indirectly by controlling the attachment state of the member that holds the bearing on the shaft. For example, in a bearing structure in which the bearing is sandwiched between the shaft and an annular member that is screw-fitted to the shaft, a pressurized load has been applied to the bearing by controlling the tightening torque of the annular member.

In the above bearing structure, when the annular member provided with the female thread that is threaded into the shaft provided with the male thread is screwed and rotated, the annular member moves by the thread pitch and presses against the bearing. By understanding the relationship between the tightening torque of the annular member and the load applied to the bearing in advance and managing the tightening torque of the annular member, it is possible to apply a desired pressurized load to the bearing.

Japanese Patent Application Publication No. 10-141364

However, in the substitute management using the tightening torque of the annular member, many factors are involved between the tightening torque of the annular member and the load applied to the bearing, and therefore the pressurized load applied to the bearing has a large variation. Factors that affect variation include the characteristics and amount of grease present inside the bearing, the characteristics and amount of the thread lock applied between the male and female threads, the manufacturing accuracy of the annular member, or the tightening torque of the annular member. Possible factors include measurement accuracy. Because the bearing life also varied due to variations in the pressurized load of the bearing, there was a possibility that some products would have a shorter lifespan than expected. Therefore, there has been a demand for a bearing structure that can appropriately apply a pressurized load to the bearing, and a method for assembling the same.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a bearing structure that can apply an appropriate pressurized load to a bearing included in the bearing structure, and a method for assembling the same.

The bearing structure of the present invention includes a shaft member, an inner race, and an outer race, the bearing is held by the shaft member with the shaft member passing through the inner race, and the bearing is rotatable by the shaft member via the bearing. A bearing structure comprising a held member held by a shaft member and a nut member fixed to a shaft member, the bearing structure further comprising a pressing member to which a load is applied between the bearing and the nut member , The pressing member has a pressed part into which a load is input, and a pressing part which transmits the load to the inner race, the pressing part has an annular shape, and the pressed part has a diameter larger than the diameter of the pressing part. The nut member has an annular shape, and has a small diameter portion having an annular shape smaller in diameter than the diameter of the pressed portion, and a large diameter portion having an annular shape larger in diameter than the diameter of the small diameter portion.

Further, in the bearing structure of the present invention, the pressing member may further include a pressed portion into which a load is input, and a pressing portion that transmits the load to the inner race.

Further, the method for assembling a bearing structure of the present invention includes a shaft member, an inner race, and an outer race, and a bearing that is held by the shaft member with the shaft member penetrating the inner race, and a bearing that is held by the shaft member through the inner race. The bearing structure includes a held member that is rotatably held relative to the shaft member, and a nut member that is fixed to the shaft member, and the bearing structure includes a holding member to which a load is applied between the bearing and the nut member. The holding member further includes a pressed part into which a load is input, and a pressing part which transmits the load to the inner race, the pressing part has an annular shape, and the pressed part has a diameter smaller than the diameter of the pressing part. The bearing also has an annular shape with a large diameter, and the nut member has a small diameter part having an annular shape with a diameter smaller than that of the pressed part and a large diameter part with an annular shape having a diameter larger than the diameter of the small diameter part. A method for assembling a structure, which includes a step of assembling a member to be held and a bearing and holding it on the shaft member, a step of holding the pressing part of the holding member in contact with the bearing and holding it on the shaft member, and a step of making contact with the pressed part. It has two contact parts, the distance between the contact parts is larger than the diameter of the small diameter part, and the length of the contact part in the direction along the axial length of the shaft member is longer than the axial length of the small diameter part. A method for assembling a bearing structure comprising the steps of: bringing each contact part of a jig formed into a small size into contact with a pressed part , and fixing a nut member to a shaft member while applying a load to the holding member with the jig. It is.

The pressing member in the method for assembling the bearing structure of the present invention may further include a pressed portion to which the load is input and a pressing portion that transmits the load to the inner race.

According to the present invention, the bearing structure includes a pressing member between the bearing and the nut member to which a load is applied, so that an appropriate preload can be applied to the bearing.

Further, according to the present invention, since the holding member includes the pressed portion into which a load is input and the pressing portion that transmits the load to the inner race, the holding member can have a simple structure.

In addition, the present invention includes a process for fixing the nut member to the shaft member while a load is applied to the pressing member, so that the bearing can be assembled with an appropriate preload applied.

Further, according to the present invention, since the assembly includes a pressing member having a pressed portion into which a load is input and a pressing portion that transmits the load to the inner race, a simple assembly method can be achieved.

It is a front sectional view showing the process of producing a bearing structure concerning an embodiment of the present invention. 2 is a front cross-sectional view showing a next step of manufacturing the bearing structure according to the embodiment of the present invention, shown in FIG. 1, and showing the bearing structure. FIG. 2 is a side view showing the pressing member in FIG. 1 . FIG. 2 is a perspective view showing the jig in FIG. 1 .

1 and 2, a method for assembling a bearing structure 100 according to an embodiment of the present invention is shown together with a front sectional view of the bearing structure 100. 1 shows the first half of the process of assembling the bearing structure 100, and FIG. 2 shows the second half of the process of assembling the bearing structure 100.

A bearing structure 100 according to an embodiment of the present invention includes a shaft member 3, a bearing 2 held by the shaft member 3, a held member 1 rotatably held by the shaft member 3 via the bearing 2, It includes a holding member 5 disposed in contact with the bearing 2, and a nut member 4 that holds the bearing 2 and the holding member 5 on the shaft member 3.

The shaft member 3 has a hollow cylindrical shaft portion 3b and a shaft flange portion 3a that is larger in diameter than the shaft cylindrical portion 3b and is formed in a disk shape and is connected to one end of the shaft cylindrical portion 3b. The shaft member 3 is a member that holds the held member 1 via the bearing 2. The shaft member center hole 3d penetrates the longitudinal center axis of the shaft cylindrical portion 3b from the other end of the shaft cylindrical portion 3b to the shaft flange portion 3a, and the shaft member 3 is fixed via this center hole or the shaft flange portion 3a. In addition, a shaft thread portion 3c is provided on the outer circumferential surface of the other end of the shaft cylindrical portion 3b, which is opposite to the shaft flange portion 3a. The shaft thread portion 3c is a male thread portion that is screwed into the nut member 4 described later. The shaft cylindrical portion 3b and the shaft flange portion 3a are integrally formed of metal.

Two bearings 2 are held on the shaft member 3. The bearing 2 is a member that is disposed between the shaft member 3 and the held member 1 and rotatably holds the held member 1. Each bearing 2 is a well-known ball bearing having an inner race 2a, an outer race 2b, and a plurality of balls 2c arranged between the inner race 2a and the outer race 2b. Two bearings 2 are arranged side by side in the axial direction of the shaft member, with the shaft member 3 passing through the inner race 2a of the bearing 2. By arranging the bearings 2 in width rows, vibration and inclination with respect to the central axis are suppressed, and the rotational state can be maintained with high precision. The fit between the inner peripheral surface of the inner race 2a of the bearing 2 and the outer peripheral surface of the shaft cylindrical portion 3b of the shaft member 3 is a clearance fit.

The held member 1 is held by the outer race 2b of the bearing 2. The held member 1 is a member that is held via a bearing 2 to a shaft member 3 so as to be relatively rotatable. A held member center hole 1a is provided in the center of the held member 1, and the inner circumferential surface of the held member center hole 1a and the outer circumferential surface of the outer race 2b are fitted together. The held member 1 is not limited to a specific device, and any device or member can be selected. The held member 1 is, for example, a rotating part of a rotary encoder. The held member 1 can also be fitted into the outer race 2b with a clearance fit.

Figure 3 shows a side view of the pressing member 5. The pressing member 5 is held by the shaft member 3. As described later, the pressing member 5 is a member that presses the inner race 2a of the bearing 2 in the axial direction when an axial load is applied by the jig 10 during assembly of the bearing structure 100. As can be seen from Figures 1 to 3, the pressing member 5 is formed in a shape in which a pressing part 5a formed in an annular shape with a diameter equal to or smaller than the diameter of the inner race 2a of the bearing 2 that it contacts, and a pressed part 5b formed in an annular shape with a diameter larger than the pressing part 5a are connected in the central axial direction. A pressing member center hole 5c is provided through the center of the pressing member 5. The pressed part 5b is a part to which a load is applied by the jig 10, as described later. The pressing part 5a is a part that transmits the load applied to the pressed part 5b to the inner race 2a of the bearing 2 that is arranged in contact with the pressing part 5a.

As shown in Figs. 1 and 2, the shaft member 3 passes through the pressing member center hole 5c of the pressing member 5, and the pressing portion 5a is held in contact with the inner race 2a. The inner diameter of the pressing member center hole 5c is formed slightly larger than the outer diameter of the shaft member 3. In other words, the pressing member 5 and the shaft member 3 are fitted together by a clearance fit. Therefore, when an axial load is applied to the pressing member 5, the pressing member 5 can easily move on the outer circumferential surface of the shaft cylindrical portion 3b of the shaft member 3. An axial load is input to the pressed portion 5b by the jig 10, and the pressing portion 5a transmits the load to the inner race 2a to press the inner race 2a. In other words, the load applied to the pressed portion 5b is the preload applied to the bearing 2. The pressing member 5 is integrally formed of metal.

FIG. 2 shows a front sectional view of the nut member 4 fixed to the shaft member 3. The nut member 4 is a member that holds the bearing 2 held on the shaft member 3 and the pressing member 5 on the shaft member 3. The nut member 4 has a small diameter part 4a which is annular and has a smaller diameter than the annular pressed part of the pressing member 5, and a large diameter part 4b which is annular and has a larger diameter than the small diameter part 4a. It is formed in a shape connected to. The large diameter portion 4b is a portion to which rotational torque is applied when tightening the nut member 4. Further, the small diameter portion 4a is a portion that is in contact with the pressed portion 5b of the presser member 5 and holds the presser member 5. A nut member center hole 4c is provided in the central shaft portion of the nut member 4, passing through from one end to the other end. A center hole threaded portion 4d is provided on the inner peripheral surface of the nut member center hole 4c from one end to the other end. The center hole threaded portion 4d is a female threaded portion, and is screwed into the shaft threaded portion 3c of the shaft member 3. The nut member 4 is integrally formed of metal.

FIG. 4 shows a perspective view of the jig 10. When assembling the bearing structure 100, a load is applied to the holding member 5 using the jig 10. As can be seen from FIG. 4, the jig 10 includes a horizontal portion 10a, a vertical portion 10b extending perpendicularly from both ends of the horizontal portion 10a, and a vertical portion 10b extending from each end of the vertical portion 10b parallel to the horizontal portion 10a. and contact portions 10c extending toward the distal ends of the vertical portions 10b. The horizontal portion 10a of the jig 10 is a portion that holds the jig 10 and applies an axial load during use.

When assembling the bearing structure 100, the jig 10 is held with the contact surface 10d on the contact portion 10c of the jig 10 in contact with the pressed portion 5b of the pressing member 5. In this state, an axial load is applied to the horizontal portion 10a, and the axial load is transmitted to the pressed portion 5b of the pressing member 5 via the contact surface 10d on the contact portion 10c. The shape of the jig 10 is formed into a substantially U-shape so that the nut member 4 can be easily attached with the contact portion 10c in contact with the pressing member 5. The jig 10 is firmly and integrally formed from metal so that it does not bend under the applied load.

As shown in FIG. 2, the nut member 4 is fixed to the shaft member 3 with the contact portion 10c of the jig 10 pressing the pressed portion 5b of the holding member 5. The shapes of the nut member 4 and the jig 10 are determined so that the nut member 4 and the jig 10 do not interfere with each other at that time. Specifically, in order to prevent the contact portion 10c of the jig 10 from interfering with the small diameter portion 4a of the nut member 4 when the nut member 4 is screwed into the shaft threaded portion 3c of the shaft member 3, the outside of the small diameter portion 4a is The diameter is smaller than the distance between the two tips of the contact portion 10c. In addition, the axial length of the small diameter portion 4a is set such that the contact portion 10c and the nut member 4 do not interfere with each other when the nut member 4 is screw-fitted to the shaft threaded portion 3c of the shaft member 3 and tightened. The contact portion 10c is longer than the axial length of the shaft member 3.

<Assembly Method>
A method for assembling the bearing structure 100 configured as above will be described.
First, a held member 1, which is held so as to be rotatable relative to a shaft member 3 and which has been prepared in advance, is assembled with a bearing 2, and the shaft member 3 is passed through the bearing 2 to hold the assembled held member 1 and bearing 2 to the shaft member 3. Next, the pressing portion 5a of the pressing member 5 comes into contact with the inner race 2a of the bearing 2 to hold it to the shaft member 3.

In this state, while applying an axial load to the pressing part 5a of the holding member 5 with the jig 10, the nut member 4 is screwed onto the shaft member 3, the nut member 4 is tightened, and the nut member 4 is attached to the shaft member. Fixed at 3. The two contact parts 10c of the jig 10 are brought into contact with the pressing part 5a of the holding member 5, and an axial load is applied to the horizontal part 10a of the jig 10 so that the load is evenly transmitted to each contact part 10c. Add. The load to be added is a pressurized load to be added to the bearing 2.

As described above, an axial load is applied to the pressing portion 5a of the holding member 5 using the jig 10. The nut member 4 is tightened to a specified torque while maintaining the state in which the axial load is applied, and the bearing 2 and the holding member 5 are fixed in a state in which the nut member 4 sandwiches the bearing 2 and the holding member 5. After completing the tightening of the nut member 4, the assembly work is completed.

The bearing structure 100 according to the embodiment of the present invention includes a pressing member 5 between the bearing 2 and the nut member 4 to which a load is applied.

Therefore, by applying a load to the pressing member 5, a preload can be applied to the bearing 2, so that an appropriate preload can be applied to the bearing 2.

The method of assembling the bearing structure 100 according to the embodiment of the present invention includes a process of holding the pressing member 5 on the shaft member 3 in contact with the bearing 2, and fixing the nut member 4 to the shaft member 3 while applying a load to the pressing member 5.

Therefore, by applying a load to the pressing member 5, a preload can be applied to the bearing 2, so that a bearing structure 100 can be assembled that can apply an appropriate preload to the bearing 2.

The bearing structure 100 is applicable as long as the shaft member 3 and the held member 1 rotate relative to each other. That is, the present invention is applicable to either the case where the shaft member 3 is fixed and the held member 1 rotates, or the case where the held member 1 is fixed and the shaft member 3 rotates.

Moreover, the shape of the jig 10 is such that it can hold the holding member 5 on the shaft member 3 in contact with the bearing 2 and fix the nut member 4 on the shaft member 3 while applying a load to the holding member 5. Can be changed as appropriate. For example, if the large diameter portion 4b of the nut member 4 has the same diameter as the small diameter portion 4a, and the nut member 4 has a cylindrical shape with the same diameter from one end to the other end, or the large diameter of the nut member 4 If the portion 4b has approximately the same diameter as the small diameter portion 4a, and the nut member 4 has a substantially cylindrical shape with a plurality of approximately the same diameters from one end to the other end, the diameter is larger than the maximum outer diameter of the nut member 4. It can be a hollow cylindrical jig. In this case, the inner diameter of the hollow part of the hollow cylindrical jig is made sufficiently large so that the nut member 4 can be tightened, or the axial length of the hollow cylindrical jig is set to the axial length of the nut member 4. It may be formed shorter than that. As yet another method, a jig fitting portion may be provided on the end surface of the nut member 4 opposite to the pressing member 5, to which a jig for easily rotating and tightening the nut member 4 is attached. Further, the outer peripheral surface of the nut member 4 near the end surface on the opposite side of the holding member 5 is formed into a well-known hexagonal shape using, for example, a bolt, and the inner surface of the corresponding jig is formed into a shape that fits into the hexagonal shape. The nut member 4 may be tightened by using a hollow jig.

1 held member, 2 bearing, 2a inner race, 2b outer race,
3 shaft member, 4 nut member, 5 pressing member, 5a pressing portion, 5b pressed portion.

Claims (2)

A shaft member (3),
a bearing (2) having an inner race (2a) and an outer race (2b), the shaft member (3) passing through the inner race (2a);
a held member (1) relatively rotatably held by the shaft member (3) via the bearing (2);
a nut member (4) provided on the shaft member (3);
a pressing member (5) to which a load is applied between the bearing (2) and the nut member (4);
Equipped with
The pressing member (5) has a pressed part (5b) into which the load is input, and a pressing part (5a) that transmits the load to the inner race (2a),
The pressing part (5a) has an annular shape, and the pressed part (5b) has an annular shape with a diameter larger than the diameter of the pressing part (5a),
The nut member (4) is
a small diameter portion (4a) having an annular shape with a diameter smaller than the diameter of the pressed portion (5b);
A bearing structure having a large diameter part (4b) having an annular shape with a diameter larger than the diameter of the small diameter part (4a) . A shaft member (3),
a bearing (2) having an inner race (2a) and an outer race (2b), the shaft member (3) passing through the inner race (2a);
a held member (1) relatively rotatably held by the shaft member (3) via the bearing (2);
a nut member (4) provided on the shaft member (3);
A pressing member (5) to which a load is applied between the bearing (2) and the nut member (4),
The pressing member (5) has a pressed part (5b) into which the load is input, and a pressing part (5a) that transmits the load to the inner race (2a),
The pressing part (5a) has an annular shape, and the pressed part (5b) has an annular shape with a diameter larger than the diameter of the pressing part (5a),
The nut member (4) is
a small diameter portion (4a) having an annular shape with a smaller diameter than the pressed portion (5b);
A method for assembling a bearing structure having a large diameter part (4b) having an annular shape with a diameter larger than the diameter of the small diameter part (4a),
a step of assembling the held member (1) and the bearing (2) integrally and holding it on the shaft member (3);
holding the pressing part (5a) of the pressing member (5) on the shaft member (3) in contact with the bearing (2);
It has two contact parts (10c) that can contact the pressed part (5b) , the interval between the contact parts (10c) is larger than the diameter of the small diameter part (4a), and the shaft member ( 3) of the jig (10), the length of the contact portion (10c) in the direction along the axial length of the jig (10) is smaller than the axial length of the small diameter portion (4a). 10c) is brought into contact with the pressed portion (5b) and the nut member (5) is provided on the shaft member (3) while applying the load to the pressing member (5) using the jig (10). A method for assembling a bearing structure comprising a process.

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