JPS61188060A - Superfinishing tool - Google Patents

Abstract

PURPOSE:To make improvements in productivity promotable, by setting up each of grindstones, one for superfinishing use and the other coarser than the former, at plural spots on a peripheral surface of a tool head retractably in a separate manner from each other, in case of superfinishing for a crankshaft or the like. CONSTITUTION:A work W is inserted into the inside of a tool head 1, and first of all, each coarse-grained second grindstone 62 is pressed to the work, rotating the work W and grinding its pheripheral surface to the extent of fixed grinding depth, then each first grindstone 61 for superfinishing use is advanced forward for pressing it to the work, making second stones 62 go back, thus superfinishing takes place. Here, both these stones 61 and 62 are advanced or retracted along a radial contact surface (a) passing an axial center 0 of the work W so that ech of retractable axes X themselves will not pass the axial center O but there is no particular hindrance, and when the first stone 61 is installed in the rear in a work rotational direction of the contact surface (a) and the second stone 62 in the front parallely, good grinding is performable. Thus, the tool head is made into contact in size and, what is more, superfinishing grinding is performable favorably in terms of productivity.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a super-finishing tool for super-finishing the circumferential surface of a ring-shaped work such as a crankshaft bottle portion or a journal portion using a grindstone.

(Prior art) - As a conventional tool of this kind, according to the specification of US 3,562,966, a ring-shaped workpiece is placed in a tool head that can be freely inserted into a tool head, and the tool head is positioned at multiple locations around the tool head, and is used for super finishing so that it can move forward and backward toward the circumferential surface of the workpiece. It is known that a grindstone is provided and the workpiece is rotated with the grindstone in pressure contact with the circumferential surface of the workpiece to super-finish the surface of the workpiece. □ (Problem to be solved by the invention) Since it takes time to grind a workpiece surface to a predetermined machining depth using only a super-finishing grindstone, it is necessary to use a grindstone that is slightly rougher than this grindstone to grind the workpiece surface. In some cases, the tool head is equipped with two types of grindstones, one for finishing and another for rougher grinding, so that machining can be carried out continuously without stopping the workpiece 6. It is hoped that this will be possible.

However, the tool head is generally formed in a C-shape with an opening for inserting and removing a workpiece on the circumferential side, and one side has an opening of 120° between both ends of the tool head on the opening side and the middle part thereof. When three grindstones are arranged radially so that their center lines pass through the workpiece axis (same arrangement as in TLSP3562966 specification), the other grindstone is placed at 120° intervals with a phase difference in the circumferential direction. In order to arrange three tools radially, it is necessary to narrow the opening and increase the circumferential angle of the tool head, and such arrangement is difficult in practice due to the ease of inserting and removing the workpiece.

An object of the present invention is to solve this problem and provide a superfinishing tool that can be processed continuously using two types of grindstones.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a tool head into which a ring-shaped workpiece can be freely inserted, and a grindstone is provided at multiple locations around the tool head so as to move forward and backward toward the surface of the workpiece. In things,
Two types of whetstones are used: a first whetstone for super-finishing and a second whetstone coarser than this, and the first whetstone and the second whetstone are placed at each location with the radial direction passing through the axis of the work as the mating surface. are arranged in parallel, and both the grindstones are capable of moving forward and backward independently of each other.

(Embodiments) The present invention will be explained with reference to illustrated embodiments. □Figures 1 and 2
Referring to the figure, (1) is a ring-shaped work W such as a crank bin.
(2) is a roughly C-shaped tool head into which the tool (
1) is attached to the front end of the slider (4) in which the support arm (2) is engaged with an elongated hole (3) formed in the support arm (2). 5), the tool head (1) can be moved along with the revolution of a crank bin or the like.

The tool head (1) is provided with grindstones located at multiple locations around the tool head (1), for example, at three locations at both ends on the opening side of the tip and at the intermediate portion, so as to be movable toward and away from the surface of the workpiece W. Here, in accordance with the characteristics of the present invention, two types of grindstones are used: a first grindstone (6,) with a super-finished finish and a second grindstone (62) with a rougher finish, and the workpiece is applied to each of the above-mentioned locations. The two grindstones (6+) (62) are installed side by side with the radial direction passing through the axis O of W as the mating surface a, and further the two grindstones (6+) (62) are
+ ) (62) can move forward and backward independently of each other.

To explain this in more detail, the body shown is the tool head (
A pair of first and second slide bars (7I) (72) that are in contact with each other at the mating surface a are slidably inserted into each of the locations of 1), and each of the bars (71) (12) At the tip of each grindstone (
6+) (6□) shall be attached, and furthermore, it shall be able to rotate freely in the circumferential direction along the grooves (1a) (1a) formed on both sides of the tool head (1) over the entire length in the circumferential direction. A pair of arc-shaped cam plates (L) (82> are provided, and a third
As shown in the figure, the first cam plate (8I) on one side engages with the pins (1a) on each of the first slide bars (1,) inserted in the three locations of the tool head (1). The scroll-shaped cam grooves (8a) on the other side, the first slide bars (7+) on the second cam plate (82), and the bins on the second slide bars (72) arranged in parallel with each other. (1a), each scroll-shaped cam groove [8a] is formed to engage with the first cam plate (8a).
,) connected to it via a lever (8b).
1) When the upper first cylinder (9I) is rotated counterclockwise in FIG. The multi-cylinder single grindstone (61) is advanced toward the workpiece W, and the second cylinder (92) on the tool head (1) is connected to the second cam plate (82) via a lever (8b). ) in the counterclockwise direction in FIG. The work was moved forward toward the work W side as shown in the figure.

In the illustrated example, a first grindstone (61) and a second grindstone (62) are arranged in parallel at the rear of the mating surface a in the work rotation direction, and in front of the first grindstone (61).

In the drawings, (lb) (1b) indicates the cover plates on both sides of the tool head (1).

(Function) After inserting the workpiece W into the tool head (1) through the opening at its tip, the workpiece W is rotated while each of the second grindstones (62) is advanced toward the workpiece W and pressed against its peripheral surface. The peripheral surface is ground to a certain machining depth, and then, while the workpiece W is rotating, each first grindstone (6,) is advanced to press against the peripheral surface of the workpiece W, and the 8th second grindstone (62
) is moved back and super finishing is performed using the 6th first grindstone (61).

Here, the 11th stone (6+) To the 211th stone (62)
The grinding wheels (6+) (62) are moved forward and backward along the mating surface a in the radial direction passing through the axis O of the workpiece W.
As shown in Fig. 4, the advance/retreat axis X itself no longer passes through the axis O of the workpiece W, but there is no particular problem. , when installing the second whetstone (62) in front of the second whetstone (62), move the whetstone (6-) along its advance/retreat axis II as shown in FIG.
Better machining can be achieved than when the x's are arranged radially so as to pass through the axis O of the workpiece W.

That is, in the arrangement shown in FIG. ') is affected by a large rotational moment M due to this frictional force F,
The front corner of the grinding wheel (6-) in the workpiece rotation direction tends to bite into the workpiece W, and this tends to cause so-called chatter vibration, which deteriorates the durability and finishing accuracy of the grinding wheel. The first and second whetstones (6,) as shown (6
In the arrangement □), l! JI! ! The line of action of the force F and the forward/backward axis X obliquely intersect, and a force 1"a, which is smaller than the frictional force F, acts in the direction orthogonal to the axis X, and the valve rotation moment M is reduced. As a result, chatter photography due to biting into the workpiece W is less likely to occur.

Furthermore, when the first grinding wheel (6th grade) finishes superfinishing, if it is suddenly removed from the workpiece W, an indentation will be left on the circumferential surface of the workpiece W. Therefore, in the arrangement shown in Figure 5, the pressing force of the grindstone against the workpiece W is reduced. Although it is necessary to perform subtle reduction control at the end of machining, in the arrangement shown in Figure 4, the first grinding wheel (6,) is pushed toward the workpiece W by the component force Fb of the frictional force F in the direction of the advance/retreat axis, and its Even if the pressing force is reduced relatively rapidly, the grinding wheel (6
I) is not suddenly separated from the workpiece W, and the pressing force can be easily controlled.

(Effects of the Invention) As described above, according to the present invention, a first grindstone for super finishing and a second grindstone coarser than the first grindstone are placed at multiple locations around the tool head, respectively, with the radial direction passing through the workpiece axis as the mating plane. These two types of grinding wheels, first and second, can be compactly incorporated into the tool head, and the second and first grinding wheels can be used to grind continuously without stopping the workpiece. This has the effect of making it possible to grind the peripheral surface of the workpiece and perform super-finishing with good productivity.

[Brief explanation of the drawing]

Fig. 1 is a front view of one example of the tool of the present invention, Fig. 2 is a rear view thereof, Fig. 3 is a sectional view taken along the line ■-■ in Fig. 1, and Fig. 4 is a cross-sectional view of the
An explanatory diagram showing the working relationship between the forces of the grinding wheel and the second grinding wheel. Fig. 5 is an explanatory diagram showing the working relationship of the forces when the grinding wheel is arranged so that its advance/retreat axis coincides with the radial direction passing through the workpiece axis. be. (1)...Tool head (61)...First grindstone (6
2)...Second grindstone W...Workpiece O...Workpiece axis a...Matching surface and 2 other people

Claims (1)

[Claims] 1. In a tool head into which a shaft-like workpiece can be freely inserted, grindstones are provided at a plurality of locations around the tool head so as to move forward and backward toward the circumferential surface of the workpiece. Two types of whetstones, a first whetstone and a second whetstone coarser than the first whetstone, are used, and the first whetstone and the second whetstone are arranged in parallel at each location with the radial direction passing through the axis of the workpiece as the mating plane, and both A super finishing tool characterized by the fact that the grindstones can move forward and backward independently of each other. 2. The superfinishing tool according to claim 1, characterized in that the first grindstone is arranged in parallel to the rear of the mating surface in the work rotation direction, and the second grindstone is arranged in front of the first grindstone.