JPH0616721U - bearing - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a bearing that can withstand loads in all directions with good balance and high accuracy as a bearing for various machine tools. [Structure] Balls 5 and 5 contacting inclined surfaces 3 and 3 of an inner race 2 having a substantially trapezoidal cross section of an inner ring 1 and inclined surfaces 11 and 11 of an outer race 9 having a generally trapezoidal cross section of an outer race 10, respectively.
And balls 8 that come into contact with the race bottoms 4 and 12, and these holes 5 and 8 are provided with oil-filling holes 14 for lubricating oil from the oil groove 13 of the outer ring 10 in the cross section of the outer ring 10. Configured.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a bearing, and in particular, as a bearing for various machine tools, it can withstand a load in all directions with good balance and high accuracy.

[0002]

[Prior art]

 In general, bearings for spindles of various machine tools such as lathes are required to withstand loads from all directions of radial load, thrust load and axial load. Therefore, various types of bearings are provided, and in particular, double type (row) thrust angular contact ball bearings are often used because they have high rigidity against a combined axial load in both thrust and radial directions.

The double thrust angular contact ball bearing has a structure in which the angular contact ball bearings are combined in the back surface, can support an axial load in both directions, has a contact angle of 50 degrees, and has high rigidity in the axial direction. It also has high rotational accuracy and is mainly used for bearing the axial load of machine tool spindles in combination with double-row cylindrical roller bearings with the same inner and outer diameters.

That is, as shown in FIG. 4, the inner races 21 and 21 are formed on the inner ring 20 at an inclination angle of 50 degrees, and the outer races 31, 31 are formed on the outer ring 30 at an inclination angle of 50 degrees. Balls 40, 40 are arranged so as to contact with and, respectively, so as to withstand loads in the thrust direction and the radial direction.

[0005]

[Problems to be solved by the device]

 However, in the case of the spindle of a machine tool, the compound type thrust angular contact ball bearing needs to withstand a load from another direction such as a radial load with high precision, and the rigidity itself tends to be insufficient. That is, in FIG. 5, when a thrust load (arrow S) acts, a component force acts to move the balls 40, 40 toward the race bottoms 22, 32, and a radial load (arrow R) acts. At this time, the balls 40, 40 exert a component force that tries to come out from the races 21, 31 outwardly, and therefore, a structure and strength for suppressing them are required.

In view of the above circumstances, the present invention provides a bearing that can withstand loads in all directions with good balance and high accuracy, as a bearing for various machine tools.

[0007]

[Means for solving problems]

 In order to solve the above-mentioned problems, a bearing according to the present invention is basically formed by annularly arranging at least three rows of balls in a circumferential direction between an inner ring and an outer ring. Provided is a configuration in which a plurality of rows of balls are arranged in an annular shape in the circumferential direction between the outer ring and the outer ring, and are arranged in a triangle in the width direction.

[0008] Furthermore, between the inner race and the outer race having an inner race and an outer race having a substantially trapezoidal cross section, three rows of a plurality of ball rows respectively contacting a pair of right and left slopes of the race and a plurality of ball rows contacting the bottom of the race. Provides an intervening configuration. In addition, the inner race has a trapezoidal cross section of the inner race and the outer ring has a trapezoidal cross section of the outer race, each of which has a ball that contacts the slope and a ball that contacts the race bottom. In addition, an oil injection hole for injecting oil from the oil groove of the outer ring is provided in the cross section of the outer ring. Further, there is provided a structure in which the balls are housed in a ball holding frame and interposed between the inner ring and the outer ring.

[0009]

[Action]

 According to the present invention having the above-described structure, since three rows of balls are interposed between the inner ring and the outer ring, the load received by the inner ring and the outer ring can be dispersed, the rigidity is high, and the durability is improved. In addition, in the case of a double thrust angular contact ball bearing, the central row of balls directly transfers the radial load to the inner and outer rings with respect to the radial load, so the rigidity is high, the durability is improved and the life is high with high accuracy. Improve.

[0010]

【Example】

 An embodiment in which the bearing according to the present invention is applied to a double thrust angular contact ball bearing will be described below with reference to the drawings. As shown in FIG. 1, an inner race 1 having an inverted trapezoidal cross section is formed on the outer peripheral surface of the inner ring 1. The inner race 2 is provided with slopes 3 and 3 on both side walls at an inclination angle of about 50 degrees with respect to a flat race bottom 4, and the slopes 3 and 3 are provided with balls 5 and 5 respectively on a ball holding frame. Balls 8 supported by ball support frames 7 are in contact with the bottoms 6 and 6 of the races. A plurality of balls 5 and 8 are arranged in a ring. The rolling groove 4a peculiar to the ball 8 is in the portion of the race bottom 4 in contact with the ball 8, and the peculiar rolling balls 4 of the ball 5 and 5 are in the portion in contact with the balls 5,5 of the slopes 3,3. Rolling grooves 3a, 3a are formed in an arc shape.

The ball holding frame 6 is composed of a ring-shaped plate body formed by bending an inclined portion 6 a having the same inclination angle as the inclination angle of the inclined surface 3 of the inner race 2, and a through hole formed in the inclined portion 6 a. A ball 5 is held in 6b. Further, as shown in FIG. 2, the ball holding frame 7 is composed of a pair of ring-shaped plate bodies in which a curved portion 7a for accommodating the balls 8 and a connecting portion 7b are formed by bending, and inside the curved portions 7a, 7a facing each other. The ball 8 is stored in.

An outer ring 10 having an outer race 9 facing the inner race 2 is crowned on the inner ring 1, and slopes 11 and 11 formed on the inner peripheral surface of the outer ring come into contact with the balls 5 and 5 to form slopes 11 and 11. A ball 8 is in contact with the race bottom 12 in between. Then, the rolling groove 12a peculiar to the ball 8 is in the portion of the race bottom 12 in contact with the ball 8, and the peculiar rolling groove 12a of the ball 8 is in the portion in contact with the balls 5 and 5 of the slopes 11, 11. The rolling grooves 11a, 11a are formed in an arc shape. Therefore, the balls 8, 5, 5 in the three rows have their own rolling grooves 4a, 12a, 3a, 11a. Therefore, the balls 5, 5, 8 in the cross section have a substantially triangular arrangement in the width direction. Further, an oil groove 13 is formed in the center of the outer peripheral surface of the outer ring 9, and an oil injection hole 14 is formed between the center ball 8 and the left and right balls 5, 5 in the cross section of the outer ring 9 from the oil groove 13. It is divided so that it can be injected, and is appropriately spaced in the circumferential direction.

Thus, as shown in FIG. 3, the movement of the main shaft in the thrust direction (arrow S) is endured because the balls 5, 5 are in contact with the inner race 2 and the outer race 9, and also in the radial direction. The movement (arrow R) is endured by the ball 8 being in contact with the bottoms 4 and 12 of the inner race 2 and the outer race 9. Further, when the main shaft thrust direction and the radial direction are moved in the combined directions (arrow Z), the balls 5 and 5 directly contact the slopes 3 and 11 of the inner race 2 and the outer race 9. By doing so, it can withstand loads in all directions.

[0014]

[Effect of device]

 As described above, according to the bearing of the present invention, at least three or more rows of balls are interposed between the inner ring and the outer ring, so that the load is dispersed, the rigidity is improved, and the life is improved. In addition, the double thrust angular contact ball bearings have high strength not only in the thrust direction but also in the radial direction, are strong against impacts, and can accurately support the spindle of machine tools such as lathes and are durable. It has the advantages of improved durability and longer life.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a partial development view of a ball holding frame.

FIG. 3 is an explanatory view of the operation of the present invention.

FIG. 4 is a sectional view of a conventional example.

FIG. 5 is an operation explanatory view of a conventional example.

[Explanation of symbols]

 1 ... Inner ring 2 ... Inner race 3,11 ... Slope 4,12 ... Race bottom 5,8 ... Ball 6,7 ... Ball holding frame 10 ... Outer ring 13 ... Oil groove 14 ... Oil injection hole

Claims (5)

[Scope of utility model registration request] 1. A bearing characterized in that at least three or more rows of balls are annularly arranged in the circumferential direction between an inner ring and an outer ring. 2. A bearing characterized in that a plurality of rows of balls are arranged in a circumferential direction between the inner ring and the outer ring in at least three rows in a ring shape and in a triangle in the width direction. 3. A plurality of ball rows which respectively contact a pair of left and right slopes of the race and a plurality of ball rows which contact the bottom of the race between an inner ring and an outer ring having an inner race and an outer race having a substantially trapezoidal cross section. Double thrust angular contact ball bearing characterized by rows intervening. 4. An inner race having a substantially trapezoidal section in cross section, and an outer race having a substantially trapezoidal cross section in outer race, each having a ball contacting the inclined plane and a ball contacting a race bottom. A bearing characterized in that an oil injection hole for injecting oil from the oil groove of the outer ring is formed in the ball in the cross section of the outer ring. 5. The bearing according to claim 1, wherein the balls are housed in a ball holding frame and are interposed between the inner ring and the outer ring.