JP2018099762A - Honing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain a non-perfect circular shape even when honing the non-perfectly circular, inner periphery of a cylindrical member.SOLUTION: A honing device comprises a honing head for honing the non-perfectly circular, inner peripheral surface of a cylindrical member. The honing head includes three grind stones at equal intervals in a circumferential direction on the outer periphery of the honing head and in positions equally distant from the rotation axis of the honing head. The three grind stones are pressed and supported in the direction of increased diameter by three respective elastic bodies identical in length and spring constant. The rotation axis of the honing head is coupled to the rotary mechanism of the honing device so as to be radially movable. During rotation, the honing head hones the inner periphery of the cylindrical member by means of the grind stones while constantly receiving reaction force of the elastic bodies from three contact points between the respective three grind stones and the inner periphery of the cylindrical member and the rotation axis of the honing head is kept automatically aligned with the position equally distant from the three grind stones.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a honing apparatus including a honing head for honing an inner peripheral surface of a cylindrical member.

  Conventionally, honing is widely used as finishing of the inner peripheral surface of a cylindrical member such as a cylinder. In the honing process, the grindstone provided on the outer periphery of the honing head is brought into contact with the inner peripheral surface of the cylindrical member, and the honing head is rotated around the axial direction to grind the inner peripheral surface of the cylindrical member.

  As a technique related to honing, for example, in Patent Document 1, four grindstones are provided on the outer periphery of the honing head at equal intervals in the circumferential direction, and each of the four grindstones is elastically expanded in the radial direction (radially outward). In the following, a technique for making the processing amount uniform by pressing and supporting the same is disclosed.

JP 2012-121078 A

  By the way, when honing the non-circular inner peripheral surface of the cylindrical member with the honing head disclosed in Patent Document 1, the processed surface has a convex portion and a concave portion, but each of the four grindstones is a pressing member of an elastic body. Under pressure, it comes into contact with the work surface.

  However, the pressing force on the four grindstones becomes non-uniform according to the unevenness of the processed surface, and in particular, the pressing force when the grindstone comes into contact with the convex portion increases, so that the convex portion is shaved first. The grinding amount of the processed surface will change. As a result, there is a problem that the inner peripheral surface of the cylindrical member cannot maintain a non-circular shape and is rounded.

  The present invention has been made in view of the above, and provides a honing device capable of maintaining a non-circular shape even when honing a non-circular inner peripheral surface of a cylindrical member. is there.

A honing apparatus according to one aspect of the present invention is provided.
A honing device comprising a honing head for honing a non-circular inner peripheral surface of a cylindrical member,
The honing head includes three grindstones at equal intervals in the circumferential direction on the outer periphery of the honing head, and at equal distances from the rotation axis of the honing head,
Each of the three grindstones is pressed and supported in the diameter increasing direction with respect to the honing head by each of three elastic bodies having the same length and spring constant.
The non-perfect circle formed by the inner peripheral surface of the cylindrical member is more than the circumscribed circle in which the tips of the three grindstones circumscribe when the three elastic bodies that press and support each of the three grindstones have a natural length. Smaller and larger than the circumscribed circle to which the tips of the three grindstones circumscribe when the three elastic bodies are compressed to the maximum,
The rotating shaft core of the honing head is connected to the rotating mechanism of the honing device so as to be movable in the radial direction,
When the honing head rotates, the rotating shaft core of the honing head always receives the reaction force of the elastic body from three contact points between each of the three grindstones and the inner peripheral surface of the cylindrical member. The inner peripheral surface of the cylindrical member is honed by the three grindstones while being automatically aligned at a position equidistant from the three grindstones.

  According to the aspect of the present invention described above, it is possible to provide a honing apparatus that can maintain a non-circular shape even when honing the inner peripheral surface of a non-circular bore of a cylindrical member.

It is upper surface sectional drawing which shows the grindstone arrangement | positioning of the honing head which concerns on related technology. It is upper surface sectional drawing which shows the grindstone arrangement | positioning of the honing head which concerns on related technology. It is upper surface sectional drawing which shows the grindstone arrangement | positioning of the honing head which concerns on related technology. It is upper surface sectional drawing which shows the grindstone arrangement | positioning of the honing head which concerns on embodiment. It is upper surface sectional drawing which shows the honing process by the honing head which concerns on related technology in time series. It is upper surface sectional drawing which shows the honing process by the honing head which concerns on embodiment in time series. It is front sectional drawing which shows the honing apparatus which concerns on embodiment. It is upper surface sectional drawing which shows the honing head which concerns on embodiment. It is an expanded front sectional view which shows the grindstone vicinity of the honing head which concerns on embodiment.

Embodiments of the present invention will be described below with reference to the drawings. In the following description, it is assumed that the inner peripheral surface of the cylindrical member that is the processing surface of the honing process is the inner peripheral surface of the cylinder bore formed in the cylinder.
<Whetstone arrangement according to the present embodiment>
First, the grinding wheel arrangement of the honing head according to the present embodiment will be described in comparison with the related art.
Like the honing head disclosed in Patent Document 1, in the case of a configuration in which a grindstone is provided on the outer circumference of the honing head at an equal distribution in the circumferential direction, and each grindstone is pressed and supported by an elastic body in the diameter expanding direction, depending on the number of grindstones When honing the non-circular inner peripheral surface of the cylinder bore, there is a problem that the pressing force to each grindstone becomes non-uniform and the inner peripheral surface of the cylinder bore becomes round. Hereinafter, the grinding wheel arrangement of the honing head will be described with reference to FIGS.

  1 to 3 are cross-sectional top views showing the grinding wheel arrangement of the honing heads 100A, 100B, and 100C according to the related art, and FIG. 4 is a top cross-sectional view showing the grinding wheel arrangement of the honing head 10 according to the present embodiment. . 1 to 4 show an elliptical shape as an example of the non-circular shape of the inner peripheral surface of the cylinder bore 90. 1 to 4 will be described assuming that the short axis direction of the ellipse is vertical and the long axis direction is horizontal.

  Four grindstones 120A are provided at equal intervals in the circumferential direction on the outer periphery of the head main body 110A of the honing head 100A according to the related art shown in FIG. However, the rotating shaft core of the honing head 100A is not aligned at a position equidistant from each of the four grindstones 120A. Therefore, the length of the elastic body 130A that presses and supports the grindstone 120A is shortened in the longitudinally oriented grindstone 120A, and the pressing force by the elastic body 130A is high. On the other hand, in the grindstone 120A that is turned sideways, the length of the elastic body 130A that presses and supports the grindstone 120A is long, and the pressing force by the elastic body 130A is low. Thus, the pressing force to each of the four grindstones 120A has become uneven.

  Further, five grindstones 120B are provided at equal intervals in the circumferential direction on the outer periphery of the head main body 110B of the honing head 100B according to the related technique shown in FIG. However, the rotation axis of the honing head 100B is not aligned at a position equidistant from each of the five grindstones 120B. Therefore, the length of the elastic body 130B that presses and supports the grindstone 120B is shortened in the vertical or substantially vertical grindstone 120B, and the pressing force by the elastic body 130B is high. On the other hand, in the grindstone 120B that has become substantially horizontal, the length of the elastic body 130B that presses and supports the grindstone 120B is long, and the pressing force by the elastic body 130B is low. Thus, the pressing force to each of the five grindstones 120B has become uneven.

  In addition, six grindstones 120C are provided at equal intervals in the circumferential direction on the outer periphery of the head main body 110C of the honing head 100C according to the related art shown in FIG. However, the rotation axis of the honing head 100C is not aligned at a position equidistant from each of the six grindstones 120C. Therefore, the length of the elastic body 130C that presses and supports the grindstone 120C is shortened in the longitudinally oriented grindstone 120C, and the pressing force by the elastic body 130C is high. On the other hand, in the grindstone 120C that is substantially horizontally oriented, the length of the elastic body 130C that presses and supports the grindstone 120C is long, and the pressing force by the elastic body 130C is low. Thus, the pressing force to each of the six grindstones 120C has become uneven.

  As described above, when four or more grindstones are provided on the outer circumference of the head body at equal intervals in the circumferential direction, the rotation shaft core of the honing head is not aligned at an equal distance from each grindstone, and the pressing force to each grindstone Has become uneven.

  On the other hand, three grindstones 12 are provided at equal intervals in the circumferential direction on the outer periphery of the head main body 11 of the honing head 10 according to the present embodiment shown in FIG. Here, the rotating shaft core of the honing head 10 is aligned at a position equidistant from each of the three grindstones 12, and this alignment is performed automatically. Therefore, in the three grindstones 12, the lengths of the three elastic bodies 13 that press and support the three grindstones 12 are substantially the same, and the pressing force by the elastic bodies 13 is substantially uniform.

<Honing processing according to the present embodiment>
Subsequently, honing processing by the honing head according to the present embodiment will be described in comparison with related technology.
FIG. 5 is a top cross-sectional view showing the honing process by the honing head 100D according to the related art in time series, and FIG. 6 is a top cross-sectional view showing the honing process by the honing head 10 according to the present embodiment in time series. is there.

  The honing head 100D according to the related art shown in FIG. 5 is provided with six grindstones 120D equally arranged in the circumferential direction on the outer periphery of the head main body 110D, and each of the six grindstones 120D is extended with an expansion cone 140D. The elastic body is not used. Further, the rotational axis of the honing head 100D is configured such that the radial position is a constant position.

  When honing the non-circular inner peripheral surface of the cylinder bore 90 with the honing head 100D, the honing head 100D is centered around the rotation axis while the six grindstones 120D are projected from the outer periphery of the honing head 100D in the diameter increasing direction. The inner peripheral surface of the cylinder bore 90 is ground by the six grindstones 120D. At this time, the rotational axis of the honing head 100D is maintained at a substantially constant position in the radial direction.

  For this reason, the grindstone 120D first comes into contact with the convex portion of the inner peripheral surface of the cylinder bore 90 and scrapes the convex portion first, so that the inner peripheral surface of the cylinder bore 90 cannot maintain a non-circular shape. , It will be rounded.

  On the other hand, in the honing head 10 according to the present embodiment shown in FIG. 6, three grindstones 12 are provided on the outer circumference of the head body 11 at equal intervals in the circumferential direction, and each of the three grindstones 12 is an elastic body 13. And press-support in the diameter-expanding direction. Therefore, the rotational axis of the honing head 10 is automatically aligned at a position equidistant from each of the three grindstones 12. Further, the honing head 10 is configured such that the rotation axis is movable in the radial direction.

  When honing the non-circular inner peripheral surface of the cylinder bore 90 with the honing head 10, the honing head 10 is rotated about the rotation axis (clockwise in the drawing) while the inner periphery of the cylinder bore 90 is rotated. While moving along the surface (moving clockwise in the drawing), the inner peripheral surface of the cylinder bore 90 is ground by the three grindstones 12.

  For this reason, during the honing process, the honing head 10 always receives the reaction force of the elastic body 13 from three contact points between each of the three grindstones 12 and the inner peripheral surface of the cylinder bore 90. Therefore, the rotational axis of the honing head 10 moves to a position where reaction forces from the three contact points are balanced, and the compressive forces generated in the three elastic bodies 13 are made substantially uniform. This three-point equilibrium state is passively generated corresponding to the unevenness of the inner peripheral surface of the cylinder bore 90. With such a mechanism, the honing head 10 rotates around the rotation axis during the honing process, and moves along the inner peripheral surface of the cylinder bore 90, and the rotation axis is always three grindstones 12. Are automatically aligned at positions equidistant from each. As a result, the three grindstones 12 always receive substantially the same pressing force, so that the convex portions on the inner peripheral surface of the cylinder bore 90 are not cut first, and the grinding amount of the processed surface is substantially uniform. It becomes. Thereby, the non-circular shape of the inner peripheral surface of the cylinder bore 90 can be maintained.

  4 and 6 schematically show the honing head 10 according to the present embodiment in order to simplify the description. For example, in FIGS. 4 and 6, the cross-sectional shape of the head main body 11 is a triangular shape, but if the three grindstones 12 are equally arranged in the circumferential direction, the cross-sectional shape of the head main body 11 is a triangular shape. A cross-sectional shape other than the shape (for example, a circular shape or a hexagonal shape) may be used.

<Specific configuration according to the present embodiment>
Subsequently, a specific configuration of the honing apparatus according to the present embodiment will be described. 7 is a front sectional view of the honing device according to the present embodiment, FIG. 8 is a top sectional view of the honing head 10 according to the present embodiment, and FIG. 9 is a grindstone of the honing head 10 according to the present embodiment. It is an expanded front sectional view of 12 vicinity.

  As shown in FIGS. 7 to 9, the head main body 11 of the honing head 10 according to the present embodiment is provided on the outer periphery of the honing head 10 at equal intervals in the circumferential direction and at the rotational axis P of the honing head 10. Three grindstones 12 are provided at equidistant positions.

  Each of the three grindstones 12 is held by a grindstone holder 14. The grindstone 12 and the grindstone holder 14 are attached to the shoe 15 by a fixing pin 18 and are pressed and supported by the elastic body 13 in the diameter increasing direction. Thereby, the grindstone 12 and the grindstone holder 14 are movable in the radial direction and the axial direction. The three elastic bodies 13 that press and support each of the three grindstones 12 have the same length and spring constant.

  An extension cone 16 that is movable in the axial direction is provided inside the head body 11. The extended cone 16 has an upper cylindrical inclined surface 161 and a lower cylindrical inclined surface 162 that are inclined in the direction of diameter reduction (inward in the radial direction; the same applies hereinafter) with the cylindrical lower portion facing downward. Two stages are formed. The shoe 15 has an upper side slope 151 and a lower side slope 152 that are inclined downward in the diameter-reducing direction, and is formed in two stages in the vertical direction. The upper side slope 151 is in contact with the upper side cylindrical slope 161, and the lower side slope A lower cylindrical inclined surface 162 abuts on the inclined surface 152.

  When the extension cone 16 is moved downward in the axial direction, the upper side slope 151 and the lower side slope 152 of the shoe 15 are pushed and expanded in the diameter increasing direction by the upper side cylindrical slope 161 and the lower side cylindrical slope 162 of the extension cone 16. Thereby, the three grindstones 12 are pushed out in the diameter increasing direction. On the other hand, when the expansion cone 16 is moved upward in the axial direction, the upper side inclined surface 151 and the lower side inclined surface 152 of the shoe 15 are drawn in the diameter reducing direction by the contraction force of the reverse donut spring 17, thereby three grindstones. 12 is pulled in the direction of diameter reduction.

  The honing head 10 is inserted into the cylinder bore 90 and performs honing on the non-circular inner peripheral surface of the cylinder bore 90. When the honing head 10 is inserted into the cylinder bore 90, it is necessary to make the outer diameter of the honing head 10 smaller than the inner diameter of the cylinder bore 90. Therefore, the expansion cone 16 is moved upward in the axial direction to reduce the three grindstones 12. The honing head 10 is inserted into the cylinder bore 90 while being pulled in the radial direction. When the honing process for the inner peripheral surface of the cylinder bore 90 is started, the expansion cone 16 is moved downward in the axial direction, the three grindstones 12 are pushed out in the diameter increasing direction, and the honing process is started in this state.

  The non-perfect circle formed by the inner peripheral surface of the cylinder bore 90 is a circumscribed circle in which the tips of the three grindstones 12 circumscribe when the three elastic bodies 13 that press and support each of the three grindstones 12 have a natural length. Than the circumscribed circle in which the tips of the three grindstones 12 circumscribe when the three elastic bodies 13 are compressed to the maximum extent (ie, the inner peripheral surface of the cylinder bore 90 is included in the circumscribed circle). (That is, the inner peripheral surface of the cylinder bore 90 includes a circumscribed circle).

  The rotating shaft core P of the honing head 10 is connected to a rotating mechanism (not shown) of the honing device via a universal joint (universal joint) 20 so as to be movable in the radial direction, and in the radial direction according to the rotation of the rotating mechanism. Move to. FIG. 7 shows a Fuchs joint as an example of the universal joint 20, but the present invention is not limited to this.

  The rotational axis P of the honing head 10 is configured to be movable in the radial direction. Further, the grindstone 12 is configured to be movable in the radial direction and the axial direction by the fixing pin 18 and the elastic body 13. Therefore, the grindstone 12 swings and tilts, and there is a possibility that biting occurs due to the edge of the grindstone 12 hitting the inner peripheral surface of the cylinder bore 90. Therefore, the shoe 15 is provided with a rocking suppression wall 153 with a gap 154 interposed so as to surround the outer peripheral surface of the grindstone holder 14, so that the grindstone 12 can move only in the gap 154 in the axial direction. Thus, the inclination of the grindstone 12 is suppressed. Further, the edge 121 on the contact surface side with the inner peripheral surface of the cylinder bore 90 in the grindstone 12 is chamfered. Thereby, biting is suppressed.

  When honing the non-circular inner peripheral surface of the cylinder bore 90 with the honing device according to the present embodiment, first, the expansion cone 16 is moved upward in the axial direction, and the three grindstones 12 are drawn in the diameter reducing direction. In this state, the honing head 10 is inserted into the cylinder bore 90. Subsequently, the expansion cone 16 is moved downward in the axial direction to push out the three grindstones 12 in the diameter expansion direction. Subsequently, the inner peripheral surface of the cylinder bore 90 is ground by the three grindstones 12 while the honing head 10 is rotated about the rotation axis P and moved along the inner peripheral surface of the cylinder bore 90.

  Here, during the honing process, the honing head 10 always receives the reaction force of the elastic body 13 from three contact points between each of the three grindstones 12 and the inner peripheral surface of the cylinder bore 90. Therefore, the honing head 10 is always automatically aligned with the rotary shaft core P at a position equidistant from each of the three grindstones 12.

  Therefore, since the three grindstones 12 always receive substantially the same pressing force during the honing process, the convex portion of the inner peripheral surface of the cylinder bore 90 is not first cut, and the machining surface The grinding amount is made substantially uniform. Thereby, the non-circular shape of the inner peripheral surface of the cylinder bore 90 can be maintained.

  When a cross hatch is formed on the inner peripheral surface of the cylinder bore 90 by honing, honing is performed by reciprocating the honing head 10 about the rotation axis P while reciprocating in the axial direction. In that case, it is desirable to select the axial lengths of the three grindstones 12 in accordance with the magnitude of the change in the axial direction of the shape of the inner peripheral surface of the cylinder bore 90. Thus, honing can be performed according to the honing pattern even when the shape of the inner peripheral surface of the cylinder bore 90 is different in the axial direction (for example, when the inner peripheral surface of the cylinder bore 90 is barrel-shaped or drum-shaped).

  Further, the honing head 10 includes only three grindstones 12 and the number of grindstones 12 is small. Therefore, when the honing head 10 is scrolled reciprocally in the axial direction while rotating around the rotation axis P, the rotary scroll ratio of the honing head 10 (the movement speed in the axial direction is divided by the rotation speed). Is an integer, the path along which the grindstone 12 moves is the same between the forward path and the return path, and boring stitches (a state in which a rough machined surface remains after boring) is likely to occur. Therefore, it is desirable that the rotary scroll ratio is a non-integer or is changed in the middle of one processing step (for example, changed to a non-integer, changed to another integer, etc.).

  In addition, the honing head 10 can reduce the pressing force to the grindstone 12 to be smaller than usual to reduce the grinding amount per stroke more than usual, and instead can increase the number of strokes in one machining process. desirable. Thereby, it contributes to the grinding amount of a processing surface being substantially equalized.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

  DESCRIPTION OF SYMBOLS 10 Honing head, 11 Head main body, 12 Grinding stone, 121 Edge, 13 Elastic body, 14 Grinding stone holder, 15 Shoes, 151 Upper side slope, 152 Lower side slope, 153 Peristaltic restraint wall, 154 Clearance, 16 Expansion cone, 161 Upper side Cylindrical slope, 162 Lower cylindrical slope, 17 Reverse donut spring, 18 Fixing pin, 20 Universal joint (universal joint), 90 Cylinder bore

Claims (1)

A honing device comprising a honing head for honing a non-circular inner peripheral surface of a cylindrical member,
The honing head includes three grindstones at equal intervals in the circumferential direction on the outer periphery of the honing head, and at equal distances from the rotation axis of the honing head,
Each of the three grindstones is pressed and supported in the diameter increasing direction with respect to the honing head by each of three elastic bodies having the same length and spring constant.
The non-perfect circle formed by the inner peripheral surface of the cylindrical member is more than the circumscribed circle in which the tips of the three grindstones circumscribe when the three elastic bodies that press and support each of the three grindstones have a natural length. Smaller and larger than the circumscribed circle to which the tips of the three grindstones circumscribe when the three elastic bodies are compressed to the maximum,
The rotating shaft core of the honing head is connected to the rotating mechanism of the honing device so as to be movable in the radial direction,
When the honing head rotates, the rotating shaft core of the honing head always receives the reaction force of the elastic body from three contact points between each of the three grindstones and the inner peripheral surface of the cylindrical member. Honing the inner peripheral surface of the cylindrical member with the three grindstones while being automatically aligned at a position equidistant from the three grindstones,
Honing device.

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