JPH03121772A - Super finishing grinding device for raceway surface of bearing inner ring - Google Patents

Abstract

PURPOSE:To reduce the weight of inertia of a grinding wheel rocking motion time and to enable a high speed rocking motion while maintaining a high accuracy, by providing a vertical moving device around the shaft center of a rocking axis so as to interpose the rocking shaft of a rocking rotation device arranged on the rocking center line of a wheel. CONSTITUTION:A vertical motion cylinder 10, in consequence a holder main body 17 is descended with a pressurizing cylinder device 18 by the oil pressure release of the lower side piston 12 of a vertical motion cylinder and the oil pressure energizing of an upper side piston 11 and the wheel tip is set at the position where a very small gap is left for the grinding place of the outer face raceway surface of a leak 3. In this case, the vertical motion cylinder 10 is fixed to the end face of the shaft end of a rocking motor 8 with the action of a wedge member 15 and the gap between the cylinder 10 and rocking motor 8 is made zero. A wheel 22 is then rocked around the rocking axis center line (circular arcuated center line) 6 by the rocking motor 8 after its pressurized contact with the work grinding face and the work 3 under rotation is subjected to grinding.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a device for super-finishing the ball raceway surface of an inner ring in a ball bearing, and particularly to a device for holding and rocking a grinding wheel that is pressed against the outer raceway surface and oscillates. Regarding the movement mechanism.

(Prior art) As a device for super finishing the outer ring or inner ring raceway surface of a ball bearing using a grindstone, a workpiece 3 is conventionally used as shown in Fig. 5.
While rotating the stick-shaped grindstone 22 around the main axis 5, the stick-shaped grindstone 22 is pressed into contact with the workpiece 3 in the radial direction, and at the same time, the grindstone 22 is pressed against the raceway surface (inner or outer raceway) on the longitudinal section of the outer ring or inner ring. There is a known structure in which the shaft is oscillated and rotated around the arcuate center line 6 of the surface. A stick-shaped grindstone is usually held by a pressure cylinder and a guide member and is brought to a position above the workpiece grinding point from the main axis direction of the workpiece, and is brought into pressure contact and around the oscillation axis (the center line of the circular arc of the raceway surface). Grinding is performed by the oscillating motion of the workpiece, and after grinding, the grindstone is raised so as to be separated from the workpiece grinding surface. Cylinder devices are generally used for the pressure contact mechanism and vertical movement mechanism of the grindstone, but conventionally the vertical movement cylinder and pressure cylinder of the grindstone are placed coaxially with each other directly above the center of the workpiece, or the grindstone is A holder (arm) for holding the workpiece was extended in the direction of the main axis of the workpiece, and the outer end of this lever was equipped with a grindstone holder support unit that included a cylinder that moved the grindstone up and down and applied pressure (for example, in JP-A-59 No. 115157), the rotation of the grindstone vertical movement cylinder is prevented by extending a bracket from the piston of the cylinder.

(Problems to be Solved by the Invention) This type of superfinishing process for the bearing raceway surface takes a particularly long time in the entire ball bearing manufacturing process, and there is a demand for improved efficiency. In order to shorten machining time, it is necessary to increase the speed of the grinding wheel's oscillation axis, but in conventional super-finishing grinding equipment, a grinding wheel vertical movement cylinder and a grinding wheel machining cylinder are installed directly above or to the side of the center of the workpiece. Since the pressure cylinders are arranged coaxially, the inertial weight when the grindstone is oscillated is large, and the grindstone pressing force changes periodically due to high-speed oscillation, making it impossible to maintain the required machining accuracy. In addition, the gap between the whetstone vertical movement cylinder and the piston induces automatic vibration due to high-speed rocking during machining, which causes a decrease in machining accuracy and increased wear on the whetstone.

The present invention enables high-speed rocking of the grinding wheel while maintaining the required accuracy and without causing self-support vibration, thereby shortening machining time, reducing grinding wheel wear, and improving efficiency. An object of the present invention is to provide a low-inertia type super-finishing grinding device for a surface.

(Means for Solving the Problems) The present invention brings a grindstone held by an arm into pressure contact with the inner raceway surface of a workpiece rotated around a main axis, and rotates the grindstone perpendicular to the main axis of the workpiece. A super-finishing grinding device for the raceway surface of a bearing inner ring that performs grinding by swinging within a plane includes a grindstone pressure cylinder device placed directly above the workpiece, and a grindstone pressure cylinder device placed on the center line of swing of the grindstone. a vertically movable part of the vertically movable device, the vertically movable part of the vertically movable device having extends above the workpiece so as to hold the grindstone pressure cylinder device, and the stick-shaped grindstone is coupled to the piston of the grindstone pressure cylinder device.

(Example) Next, an example of the present invention will be described with reference to the drawings.

1 and 2 are an overall front view and a side view of a super-finishing grinding device according to an embodiment of the present invention, and FIG. 3 is an I[[-[ 11 is an enlarged sectional view taken along line 11. FIG. A workpiece 3 is held on the output shaft of a main shaft motor 2 on a bed 1 via a backing plate 4 by an inner shoe and a brake intermediate plate (air bearing), not shown, and is driven to rotate around its main axis line 5. The workpiece 3 serving as the inner ring of the bearing has a ball raceway surface on its outer surface. This outer raceway surface 3a has a concave arc shape. 6 is the upper circular arc centerline of the outer raceway surface when viewed in the longitudinal section of the workpiece 3.

A table 7 (FIG. 2) is provided on the same bed, adjacent to the mounting portion of the spindle motor 2, and whose displacement can be adjusted in the direction of the main axis 5 of the workpiece 3 according to the width of the workpiece 3. A swing motor 8 of a swing rotation device, which will be described later, is provided on this table so as to coincide with the arcuate center line 6 of the workpiece 3. An end plate 9 is fixed to the outer periphery of the output shaft 13 (FIG. 3) of the I8 motor 8, and the shaft end of the output shaft is connected to the center hole 10a of the vertical motion cylinder 10, which has a pair of cylinder chambers 10b in opposite directions. is inserted into. A piston 11.12 is inserted into each cylinder chamber and these pistons 11.1
2 protrudes from the cylinder chamber 10b into the center hole 10a of the cylinder 10, and is always in contact with the outer circumference of the motor output shaft 13 so as to sandwich it therebetween. Each piston 11.1
2, a vertical movement fluid such as pressure oil is introduced through the vertical movement cylinder 10, and by switching the hydraulic pressure introduced into the pistons 11 and 12 on both sides, the vertical movement cylinder! 0 moves up and down in the axial direction of the piston.

FIG. 3 shows a state in which the vertical cylinder 10 is lowered. From this state, pressure oil is applied to the rear end of the upper piston 11, and at the same time, the hydraulic pressure at the rear end of the lower piston 12 is released, so that the vertical cylinder 10 is lowered. The pistons 11 and 12 therefore move upward by a distance α in the figure with respect to the swing motor output shaft 13.

As shown in FIG. 4, dovetail grooves 14 surrounding the end plate 9 are formed on both outer sides of the vertically movable cylinder 10, and a pair of dovetail grooves 14 with a tapered surface are formed between the dovetail grooves and the end plate 9. The wedge member 15 is housed with a slight gap 25 between it and the swing motor.

A recess 16 serving as a fluid pressure chamber is formed in the end surface of the wedge member 15 on the vertical movement cylinder 10 side, and pressurized fluid such as pressurized air or pressure oil is supplied to this recess 16 from the vertical movement cylinder 10 side. 15 is pushed toward the end plate 9 side and wedge-engaged between the end plate 9 and the dovetail groove 14 of the vertically moving cylinder 10, so that the vertically moving cylinder 10 is clamped to the swing motor 8 side. A base portion of a holder body 17, which is generally U-shaped (see FIG. 2), is fixed to the end surface of the vertically movable cylinder 10 on the workpiece side.

The holder main body 17 extends above the workpiece 3, and a grindstone pressurizing cylinder device is inserted into a vertical portion of the main body 17 above the workpiece. The vertically movable cylinder 10 and the holder main body 17 constitute a vertically movable cylinder slide 20 according to the present invention.

The grinding wheel pressure cylinder device 18 is placed directly above the grinding surface of the workpiece 3, and is located in a range on both sides of the workpiece vertical centerline 19 within a vertical plane orthogonal to the arcuate centerline 6 of the outer raceway surface of the workpiece 3. (see imaginary line in FIG. 1), and the center of the swing at this time coincides with the arc center line 6, that is, the center of the output shaft of the swing motor 8. The upper end of a stick-shaped grindstone 22 is fixed to the lower end of the pressure piston 26 of the pressure cylinder device 18 . The stick-shaped grindstone 22 passes through a grindstone guide 23 provided at the lower end of the pressure cylinder device 18 and extends to a workpiece grinding position. An oval ring-shaped sealing member 27 is attached to the grindstone guide 23, and the lower part of the grindstone is clamped by this seal member to guide the grindstone when it is pressurized.

In the above-described configuration, first, the workpiece 3 is attached to the output shaft of the main shaft motor 2 and rotated. At this time, the vertically movable cylinder 10 of the vertically movable cylinder slide 20 is raised to the upper limit position by the hydraulic pressure acting on the lower piston 12. Then, the hydraulic pressure of the lower piston 12 of the vertically moving cylinder 10 is released,
The vertically moving cylinder 1 is activated by the hydraulic pressure of the upper piston 11.
0, therefore the holder main body 17 is a pressurized cylinder device W18
At the same time, the grinding wheel descends, and the tip of the grinding wheel comes to a position leaving a very small gap with respect to the grinding location on the outer raceway surface of the workpiece 3. At this time, pressurized fluid is supplied from the clamping fluid ports 24 on the left and right sides of the vertical cylinder to the recess 16 of the wedge member 15, and due to the wedge engagement, the vertical cylinder IO is connected to the end plate of the shaft end of the swing motor 8. It is fixed at 9. At this clamp portion, the gap between the vertically movable cylinder 10 and the swing motor 8 becomes zero.

After the vertical movement cylinder 10 is clamped, the pressure cylinder device 18 is energized to bring the grindstone 22 into pressure contact with the grinding surface of the workpiece, and the swing motor 8 moves the grindstone 22 along its swing axis center line (
It swings around the arc center line 6) and starts the grinding operation. Rough finishing and finishing are time-controlled using a timer. After machining is completed, release the pressure of the pressure cylinder device Z18, release the fluid pressure of the wedge 2 fluid pressure clamp device, and release the vertical movement cylinder 1.
The grindstone 22 is raised by switching the piston pressure of O, and the workpiece 3
is taken out and the next workpiece is loaded.

(Effects of the Invention) As explained above, in the present invention, the cylinder and piston that move the grindstone up and down are provided symmetrically around the outer circumference of the swing shaft of the swing motor so as to sandwich the swing shaft of the swing motor. The inertial weight during dynamic operation is reduced, and high-speed oscillating operation is possible while maintaining high accuracy, improving machining efficiency. In addition, since the vertical sliding part is clamped during swinging using a wedge action, the gap between the motor side and the vertically moving part can be reduced to zero, unlike the conventional cylinder piston lock. This eliminates automatic vibration, reduces grindstone wear, and reduces the frequency of grindstone replacement, resulting in lower costs and higher precision.

[Brief explanation of drawings]

1 and 2 are an overall front view and a side view of a super-finishing grinding apparatus according to an embodiment of the present invention, FIG. 3 is a cross-sectional view taken along the line ■-■ of FIG. 1, and FIG. FIG. 5 is a cross-sectional view taken along the line V-IV of FIG. 5, which shows the relationship between the workpiece and the grindstone in superfinishing. 2... Main shaft motor, 3... Workpiece, 5... Main axis line, 6... Arc center line, 7... Table, 8... Rocking motor, 9... End plate, 10 ... Vertical cylinder, 11.12... Piston, 13... Rocking motor output shaft, 15... Wedge member, 16... Recess, 17... Holder body, 8... Grindstone Pressure cylinder device, 0... Vertical cylinder slide, 2... Grindstone, 23... Grindstone guide, 6... Pressure piston.

Claims (2)

[Claims] (1) Grinding is performed by bringing the tip of a stick-shaped grindstone into pressure contact with the outer raceway surface of a workpiece that is being rotated around the main axis, and by swinging the grindstone within a vertical plane that includes the main axis of the workpiece. In a super-finishing grinding device for a bearing inner ring raceway surface, a grindstone pressurizing cylinder device disposed directly above the workpiece, an oscillating rotation device disposed on the center line of oscillation of the grindstone, and the oscillating rotation and a vertical movement device disposed around the axis of the swing shaft of the device so as to clamp the swing shaft of the device,
The vertically movable part of the vertically movable device extends above the workpiece so as to hold the grindstone pressurizing cylinder device,
A super-finish grinding device for a bearing inner raceway surface, wherein the stick-like grindstone is coupled to a piston of the grindstone pressurizing cylinder device. (2) The rocking and rotating device is held on a table whose displacement can be adjusted in the direction of the main axis of the workpiece, and the vertically moving device is connected to a pair of piston rods that sandwich the rocking shaft of the rocking and rotating device. A vertically moving cylinder slide that accommodates a piston rod and holds the grindstone pressurizing cylinder device, and further includes a wedge type hydraulic clamp provided between the swinging rotation device and the vertically moving cylinder slide. 2. A super-finishing grinding device for a bearing inner raceway surface according to claim 1.