JP2005199378A - Method of honing inner peripheral surface of cylinder bore and device of honing inner peripheral surface of cylinder bore - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of honing capable of assuring roundness of a cylinder bore even when load due to bolt fastening is added to a cylinder block when a cylinder head is fixed by bolt fastening through a cylinder head gasket along a peripheral edge of the cylinder bore on the cylinder block having the cylinder bore, and also to provide a device of honing. <P>SOLUTION: A dummy head 41 is mounted on an upper deck 19 of an inner peripheral block 12 for mounting a cylinder liner part 24 on a pedestal 33 to allow a protruded pushing part 46 to abut on the peripheral edge part of the cylinder bore 11. The dummy head 41 is fastened to the inner peripheral block 12 with a bolt 16 and an external peripheral surface 25 of the cylinder liner part 24 is brought into contact with a support surface 40 by a piston 38 of a hydraulic cylinder 34 to be pressed inward in a radial direction. In this state an inner peripheral surface 11a of the cylinder bore 11 is honed in a perfect circle shape with a grinding tool 49. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a honing method for an inner peripheral surface of a cylinder bore and a honing apparatus for an inner peripheral surface of a cylinder bore.

  In general, a cylinder bore formed in a cylinder block is honed on its inner peripheral surface by a honing apparatus in which grindstones are arranged in an annular shape in order to increase the accuracy of roundness. After the inner peripheral surface of the cylinder bore is honed as described above, the cylinder head is assembled and fixed onto the cylinder block by bolt fastening with a cylinder head gasket as a kind of seal member interposed. Recently, in order to reduce the weight of the cylinder block, the peripheral wall of the cylinder bore (that is, the cylinder liner portion in the cylinder block) tends to be formed thin.

  For this reason, even if the roundness of the inner peripheral surface of the cylinder bore is increased in advance by honing, the roundness of the cylinder bore is reduced when the cylinder head is assembled and fixed on the cylinder block by bolt fastening. was there. That is, there is a problem that stress is generated in the cylinder block (particularly, the cylinder liner portion) due to the load applied with the bolt fastening, which causes the cylinder bore to be deformed into a non-circular shape. Therefore, in order to deal with such a problem, as described in, for example, Patent Documents 1 to 3, for example, the deformation of the cylinder bore that occurs when the cylinder head is assembled and fixed on the cylinder block by bolt fastening is recently performed. A honing technique for a cylinder bore inner peripheral surface that has been considered in advance has been proposed.

  First, in the honing technique described in Patent Document 1, the load load mechanism applies a load toward the center of the cylinder bore to the upper end portion of the cylinder liner portion in the cylinder block, and the cylinder liner portion is deformed by the load load. In the generated state, the inner peripheral surface of the cylinder bore is honed into a perfect circle. Then, after the honing process, when the load load is released, the cylinder bore honed into a perfect circle shape is deformed into a non-circular shape by a restoring action accompanying the load load release. Therefore, when the cylinder head is actually assembled and fixed by bolt fastening on the cylinder block after such honing processing, the cylinder liner portion is deformed by the load applied based on the bolt fastening at that time, Following the deformation of the cylinder liner portion, the cylinder bore is also deformed from the non-circular shape to the perfect circular shape.

  Next, in the honing technique described in Patent Document 2, in contrast to the honing technique described in Patent Document 1, the inner peripheral surface of the cylinder bore is not a perfect circle but a non-circular shape during the honing process. I try to process. That is, in the honing technique disclosed in Patent Document 2, an error curve with respect to the roundness of a cylinder bore that is actually assembled and fixed in advance by bolt fastening on a cylinder block and deformed into a non-round shape based on the bolt fastening. Is measuring. And, for the inner peripheral surface of the cylinder bore of the cylinder block after removing the cylinder head, the movement in the radial direction of the grindstone serving as the honing means is controlled based on the control data obtained from the error curve. The inner peripheral surface of the cylinder bore has a non-circular shape before the cylinder head is assembled and fixed.

In the honing technique described in Patent Document 3, a dummy head simulating a cylinder head is assembled by bolt fastening to the upper end surface of a so-called closed deck structure cylinder block which is closed without opening a water jacket on the upper surface side. I try to fix it. That is, the dummy head is assembled and fixed to create a state that simulates the case where the cylinder head is actually fixed by bolt fastening, and the inner peripheral surface of the cylinder bore is honed into a perfect circle in the simulated state. ing. Therefore, in the case of the honing technique of Patent Document 3, as in the case of the honing technique of Patent Document 1, when the dummy head is removed after the honing process, the honing process is performed in a perfect circle shape. The cylinder bore is deformed into a non-circular shape by the restoring action accompanying the release of the load. When the cylinder head is actually assembled and fixed by bolt fastening on the cylinder block after the honing process, the cylinder liner portion is deformed based on the load applied by the bolt fastening at that time. Is deformed from a non-circular shape to a perfect circular shape.
JP 2000-271853 A (Claim 1, FIG. 1) JP 2000-291487 A (Claim 5, FIG. 5) Japanese Patent Laid-Open No. 3-26460 (Claim 1 Claim, FIG. 1)

  However, each of the honing techniques disclosed in Patent Documents 1 to 3 has a problem that the cylinder bore does not have a desired circular shape when the cylinder head is actually assembled and fixed on the cylinder block by bolt fastening. there were. That is, when the cylinder head is actually assembled and fixed on the cylinder block by bolt fastening, a cylinder head gasket (seal member) is usually interposed between the cylinder head and the cylinder block along the periphery of the cylinder bore. The For this reason, when the cylinder head is actually assembled and fixed, the surface pressure from the cylinder head gasket is applied to the peripheral portion of the cylinder bore and the degree of deformation of the cylinder bore is increased. The deformation amount of the cylinder bore due to the surface pressure from the cylinder head gasket was not considered at all. Therefore, as described above, in each of the honing techniques disclosed in Patent Documents 1 to 3, even when the cylinder bore is deformed from a non-circular shape with a load applied based on bolt fastening at the time of actual assembly and fixing of the cylinder head, as desired. It was never a perfect circle.

  In addition, the honing technique disclosed in Patent Document 1 applies a load radially inward by a load-loading mechanism that abuts and engages the pressing piece with the outer peripheral surface of the upper end portion of the cylinder liner portion. The roundness over the entire inner peripheral surface (particularly the roundness at the lower end of the cylinder liner portion) has not been improved.

  In the case of the honing technique disclosed in Patent Document 2, it is necessary to control the movement of the grindstone in the honing machine in units of several tens of μm according to the correction amount obtained from the error curve. Therefore, there is a problem that the configuration for controlling the grindstone operation becomes complicated and the cost of the apparatus increases.

  Also, in the honing technique disclosed in Patent Document 3, the cylinder bore inner peripheral surface of the cylinder block in which the cylinder liner portion constituting the peripheral wall of the cylinder bore and the cylinder outer wall portion positioned on the outer peripheral side of the cylinder liner portion are integrated. Since it is a technique for honing, there is a problem that the honing apparatus becomes large and the cost of the apparatus also increases. Incidentally, honing is performed on the inner peripheral surface of the cylinder bore of the cylinder block in which the cylinder liner portion and the cylinder outer wall portion are integrated. It was also possible to point out each of the two honing techniques.

  The present invention has been made in view of such circumstances. The purpose is that when the cylinder head is assembled and fixed by bolt fastening on the cylinder block in which the cylinder bore is formed with a cylinder head gasket interposed along the periphery of the cylinder bore, Even if it is added to the block, it is to ensure good roundness of the cylinder bore. In addition, another object is to reliably improve the roundness over the entire inner peripheral surface of the cylinder bore and to contribute to cost reduction with a simple and small-sized device configuration.

In the following, means for achieving the above object and its effects are described.
(means)
First, the invention according to claim 1 relating to the honing method for the inner peripheral surface of the cylinder bore is a cylinder head gasket on the cylinder block when honing is performed on the inner peripheral surface of the cylinder bore formed in the cylinder block. Is applied to the upper end surface of the cylinder block at the honing position where a pressing load corresponding to the load applied to the upper end surface of the cylinder block is fixed to the upper end surface of the cylinder block. In this state, the entire inner peripheral surface of the cylinder bore is subjected to honing so that the cross-sectional shape of the cylinder bore becomes a perfect circle.

  According to a second aspect of the present invention, in the honing process for the inner peripheral surface of the cylinder bore according to the first aspect, the outer peripheral surface of the cylinder liner portion that becomes the peripheral wall of the cylinder bore in the cylinder block when performing the honing process. Is supported with a pressing load radially inward.

Next, the invention according to claim 3 relating to the honing apparatus for the inner peripheral surface of the cylinder bore is the honing apparatus for the inner peripheral surface of the cylinder bore for honing the inner peripheral surface of the cylinder bore formed in the cylinder block. When the cylinder head is assembled and fixed by bolt fastening with the cylinder head gasket interposed along the periphery of the cylinder bore, a pressing load equivalent to the load applied to the upper end surface of the cylinder block is placed at the honing position Pressing load means for applying to the upper end surface of the cylinder block;
Honing means for honing the entire inner peripheral surface of the cylinder bore so that the cross-sectional shape of the cylinder bore becomes a perfect circle when the pressing load is applied to the upper end surface of the cylinder block by the pressing load means. It is characterized by.

  According to a fourth aspect of the present invention, in the honing apparatus for an inner peripheral surface of the cylinder bore according to the third aspect, the pressing load means has a pressing portion having a convex shape whose cross-sectional shape corresponds to the cylinder head gasket. A pressing load member and the pressing load member for holding the pressing load member in a state where a pressing load corresponding to the load is applied to the upper end surface of the cylinder block by abutting the peripheral portion of the cylinder bore in the upper end surface of the cylinder block. And a pressing load state holding member.

  According to a fifth aspect of the present invention, in the honing apparatus for the inner peripheral surface of the cylinder bore according to the third or fourth aspect, the outer peripheral surface of the cylinder liner portion that becomes the peripheral wall of the cylinder bore in the cylinder block is radially inward. It is further characterized by further comprising a pressing support means for pressing and supporting with a pressing load.

  According to a sixth aspect of the present invention, in the honing apparatus for an inner peripheral surface of the cylinder bore according to the fifth aspect, the pressing support means is in a state where the pressing load is applied to the upper end surface by the pressing load means. A pressing support member having a surface-shaped support surface corresponding to the outer peripheral surface of the cylinder liner portion in a cylinder block; and the pressing support member is in surface contact with the outer peripheral surface of the cylinder liner portion. And a pressing support state holding member for holding the outer peripheral surface in a state of being pressed and supported radially inward.

According to a seventh aspect of the present invention, in the honing apparatus for an inner peripheral surface of the cylinder bore according to any one of the third to sixth aspects, the cylinder block is configured to place and support the cylinder head. Are divided into an inner peripheral block in which an upper deck portion is formed and an outer peripheral block in which an outer wall portion of a cylinder into which the inner peripheral block is inserted and assembled from above is formed. It is arranged at a processing position.
(Function and effect)
In the first and third aspects of the invention, when the honing process is performed, the cylinder block is added to the cylinder block when the cylinder head is actually assembled and fixed by bolt fastening with a cylinder head gasket interposed. A pressing load corresponding to the load that will be applied is applied to the upper end surface of the cylinder liner. Therefore, the cylinder liner portion (and cylinder bore) of the cylinder block that has been subjected to such a pressing load is deformed into a non-circular shape. Note that the amount of deformation at that time corresponds to the pressing load corresponding to the load based on the bolt tightening with the cylinder head gasket interposed, so the same conditions as when the cylinder head is actually assembled and fixed It becomes the amount of deformation below.

  In that state, the entire inner peripheral surface of the cylinder bore is honed so that the cross-sectional shape of the cylinder bore is a perfect circle, and then the pressing load applied to the upper end surface of the cylinder liner portion is released. . Then, the cylinder liner part (and cylinder bore) in the cylinder block is deformed in the restoring direction based on the release of the pressing load. Specifically, the outer peripheral surface of the cylinder liner portion that was non-circular at the end of honing is deformed into a perfect circle, and the inner periphery of the cylinder bore that has been honed into a perfect circular shape at the end of honing The surface is deformed into a non-circular shape.

  Therefore, after that, when the cylinder head is actually assembled and fixed by bolt fastening with the cylinder head gasket interposed on the cylinder block subjected to the honing process, the cylinder liner portion is loaded with the load based on the bolt fastening. (And cylinder bore) are deformed, but at that time, the cylinder bore is deformed into a perfect circular shape as desired. Therefore, when the cylinder head is assembled and fixed by bolt fastening with a cylinder head gasket interposed on the cylinder block in which the cylinder bore is formed, the load load associated with the bolt fastening is applied to the cylinder block. Even if added, the roundness of the cylinder bore can be secured satisfactorily.

  By the way, when the entire inner peripheral surface of the cylinder bore that has been deformed into a non-circular shape is subjected to a pressing load on the upper end surface of the cylinder block, the cylinder that forms the peripheral wall of the cylinder bore is honed to a perfect circular shape. A pressing force to the outer side in the radial direction acts on the liner portion. For this reason, when the pressing force is large, the cylinder liner portion is deformed and deformed outward in the radial direction due to the pressing force. It may be different from the deformed state when assembled and fixed to. In this regard, considering the improvement in roundness over the entire inner peripheral surface of the cylinder bore when the cylinder head is actually mounted and fixed on the cylinder block, the cylinder liner portion is moved radially outward during such honing. It is preferable that there is no distortion deformation.

  Therefore, in the inventions according to claims 2 and 5, in order to prevent such distortion deformation to the radially outer side during the honing process of the cylinder liner portion, the outer peripheral surface of the cylinder liner portion exerts a pressure load on the radially inner side. It is supported with it. Therefore, the cylinder bore inner peripheral surface of the cylinder block is honed under the same conditions as when the cylinder head is actually assembled and fixed on the cylinder block by bolt fastening. It is possible to reliably improve the roundness over the entire circumferential surface.

  According to a fourth aspect of the present invention, in the state in which the pressing load member constituting the pressing load means makes the convex pressing portion abut on the peripheral portion of the cylinder bore in the upper end surface of the cylinder block, the pressing portion Is held by the pressing load state holding means in a state where a pressing load corresponding to the load is applied to the upper end surface of the cylinder liner portion. That is, the surface pressure (pressing load) corresponding to the surface pressure (load) of the cylinder head gasket when the cylinder head is actually assembled and fixed on the cylinder block by bolt fastening is from the convex pressing portion of the pressing load member. Applied to the upper end surface of the cylinder block. For this reason, the cylinder liner portion and the cylinder bore in the cylinder block are in the same deformation state as when the cylinder head is actually assembled and fixed on the cylinder block by bolt fastening due to the pressing load from such a pressing portion. Therefore, the cylinder bore inner circumferential surface of the cylinder block arranged at the honing position is provided with a simple configuration of the load load means composed of the pressure load member and the pressure load state holding member, thereby achieving a perfect circular shape as desired while reducing costs. Honing can be done.

  According to a sixth aspect of the present invention, in the state where the pressing support means constituting the pressing support means makes the support surface come into surface contact with the outer peripheral surface of the cylinder liner portion, the support surface makes the outer peripheral surface of the cylinder liner portion. It is held by the pressing support state holding member in a state of being pressed and supported radially inward. That is, honing the inner peripheral surface of the cylinder bore to maintain the same outer peripheral surface shape (non-circular surface shape) as the cylinder liner when the cylinder head is actually assembled and fixed on the cylinder block by bolt fastening. The outer peripheral surface of the cylinder liner portion is supported with a pressing load inward in the radial direction. For this reason, the cylinder liner retains the same deformation state as when the cylinder head is actually assembled and fixed on the cylinder block by bolt tightening, even if a radially outward pressing force is applied during honing. To do. Therefore, the roundness over the entire inner peripheral surface of the cylinder bore after assembly is reliably improved while providing cost reduction means having a simple configuration including the pressure support member and the pressure support state holding member. be able to.

  In the invention according to claim 7, the cylinder block is divided into the inner peripheral block and the outer peripheral block, and the cylinder bore to be honed is formed in the inner peripheral block. Need only be placed. Accordingly, the honing apparatus can be reduced in size, and the apparatus cost related to the honing process can be reduced.

  Hereinafter, an embodiment in which the present invention is embodied in a honing method and an honing apparatus for a cylinder bore inner peripheral surface in a split cylinder block of a water-cooled engine will be described with reference to FIGS.

First, the cylinder block 10 in this embodiment is demonstrated.
As shown in FIGS. 1A, 1B, and 2, the cylinder block 10 includes an inner peripheral block 12 in which a plurality of (four in this embodiment) cylinder bores 11 are formed, and the inner peripheral block 12 is located upward. It is comprised as a division | segmentation type | mold cylinder block divided | segmented into the outer periphery block 13 inserted and assembled | attached from. In a state where the inner peripheral block 12 is inserted and assembled to the outer peripheral block 13, the cylinder head 14 is placed on the inner peripheral block 12 via a cylinder head gasket 15 as shown in FIG. 2. At that time, the cylinder head gasket 15 is interposed between the upper end surface 12 a of the inner peripheral block 12 and the bottom surface 14 a of the cylinder head 14 along the periphery of the cylinder bore 11. In this state, the cylinder head 14 is fastened onto the cylinder block 10 by a bolt 16. Then, the main body of the water-cooled engine 18 having the water jacket 17 through which the cooling water flows around the cylinder bore 11 is assembled.

  An upper deck portion 19 serving as a placement portion for the cylinder head 14 is formed on the upper portion of the inner peripheral block 12. In the upper deck portion 19, bolt insertion holes 20 for inserting the bolts 16 are formed, and oil holes 21, blow-by gas holes 22, cooling water holes 23 and the like are formed. A cylinder liner portion 24 serving as a peripheral wall of the cylinder bore 11 is formed below the upper deck portion 19. The cylinder liner portion 24 is formed in a shape in which four cylindrical bodies serving as cylinder liners of the respective cylinders are continuously connected, and an outer peripheral surface 25 of the cylinder liner portion 24 formed on the outer surface of each cylindrical body is An inner peripheral side wall surface for the water jacket 17 is formed.

  A crankcase portion 28 having a substantially skirt shape when viewed from the side is formed at the lower portion of the outer peripheral block 13. A cylinder outer wall portion 29 into which the cylinder liner portion 24 of the inner peripheral block 12 is inserted and assembled from above is formed above the crankcase portion 28. An inner peripheral surface 30 of the cylinder outer wall portion 29 is formed to have a substantially annular shape corresponding to the outer peripheral surface 25 of the cylinder liner portion 24 opposed to the inner peripheral surface 30, and the outer peripheral side wall surface with respect to the water jacket 17. Configure. In addition, a cooling water port 29a communicating with the water jacket 17 is formed on the side surface of the cylinder outer wall portion 29. Although not shown, the bolt insertion hole 20 formed in the upper deck portion 19 of the inner peripheral block 12, the oil Bolt fastening holes, oil passages, and blow-by gas passages are formed at positions corresponding to the holes 21 and the blow-by gas holes 22, respectively.

Next, the honing apparatus 31 in this embodiment will be described.
As shown in FIGS. 3 and 4, the honing apparatus 31 includes a long rectangular base 32, and a pair of left and right pedestals 33 on which the inner peripheral block 12 can be placed are provided on the base 32. 32 is formed to be bulkier than the upper surface portion. The upper surface of the pedestal 33 is the honing position, and the width dimension between the outer surfaces of the left and right pedestals 33 (the dimension between the outer surfaces in the left and right directions in FIGS. 3 and 4) is the cylinder liner portion 24. It is formed smaller than the diameter of the outer peripheral surface 25. That is, when the cylinder liner portion 24 is placed on the pedestal (honing position) 33, the cylinder liner portion 24 has a portion in the vicinity of the outer peripheral surface 25 located outside the edge corner portion of the pedestal 33. A little overhanging.

  On the base 32, hydraulic cylinders 34 functioning as pressing support means are disposed at positions facing each other across the base 33. The hydraulic cylinder 34 includes a cylinder body 36 to which hydraulic oil is supplied from a hydraulic source (not shown) via a pipe 35, and a coil spring 37 is interposed between the cylinder body 36 and the side surface of the pedestal 33. A piston 38 is provided so as to be movable in the axial direction. That is, when hydraulic oil is supplied into the cylinder body 36 from the pipe 35, the piston 38 moves forward in the direction of the pedestal 33 against the urging force of the coil spring 37 and is placed on the pedestal 33. The outer peripheral surface 25 of the cylinder liner portion 24 is pressed and supported with a pressing load inward in the radial direction.

  The piston 38 has a support portion 39 having a substantially arc shape in plan view along the outer peripheral surface 25 of the cylinder liner portion 24 on the front end side, and the support surface 40 configured by the front surface of the support portion 39 is The cylinder liner portion 24 (cylinder bore 11) is formed in a surface shape corresponding to the outer peripheral surface 25 of the cylinder liner portion 24 when the shape is changed from a perfect circle shape to a non-perfect circle shape. Specifically, when the cylinder head 14 is actually assembled and fixed by the fastening force of the bolt 16 with the cylinder head gasket 15 interposed on the cylinder block 10, the cylinder head 14 is deformed by receiving a load based on the bolt fastening. It is formed in a surface shape corresponding to the outer peripheral surface 25 of the cylinder liner portion 24 in the state (see FIG. 5A). In this embodiment, the piston 38 having the support surface 40 that can come into surface contact with the outer peripheral surface 25 of the cylinder liner portion 24 functions as a pressing support member, and supplies hydraulic oil to the cylinder body 36 and the cylinder body 36. The piping 35 to function as a pressing support state holding member.

  In addition, the honing apparatus 31 includes a dummy head 41 formed so as to be placed on the upper end surface 12 a of the inner peripheral block 12. The dummy head 41 includes a peripheral wall portion 42 having a shape substantially corresponding to the cylinder liner portion 24 shown in cross section in FIG. 4 and a flange portion 43 integrally formed radially outward from the lower portion of the peripheral wall portion 42. I have. A tool insertion hole 44 having substantially the same diameter as the cylinder bore 11 of the inner peripheral block 12 is formed on the inner peripheral side of the peripheral wall portion 42, and a bolt formed on the upper deck portion 19 on the inner peripheral block 12 side in the flange portion 43. A similar bolt insertion hole 45 is formed at a position corresponding to the insertion hole 20.

  A convex pressing portion 46 having a cross-sectional shape corresponding to the cylinder head gasket 15 is formed on the bottom surface 41 a that faces the upper end surface 12 a of the inner peripheral block 12 in the dummy head 41. That is, the dummy head 41 is placed on the upper end surface 12a of the inner peripheral block 12 in a state where the bolt insertion hole 45 of the flange portion 43 is aligned with the bolt insertion hole 20 of the upper deck portion 19 on the inner peripheral block 12 side. In this case, the pressing portion 46 is configured to come into contact with the peripheral portion of the cylinder bore 11. In this state, as shown in FIG. 3, when the bolt 16 inserted into both the bolt insertion holes 20 and 45 is tightened by the nut 47, the bolt is fastened and the upper surface of the inner peripheral block 12 (cylinder block 10) is fastened. A pressing load that can deform the cylinder liner portion 24 (and the cylinder bore 11) from the pressing portion 46 to a non-circular shape is applied to the end surface 12a. Therefore, in the present embodiment, the dummy head 41 having the convex pressing portion 46 functions as a pressing load member, and the inner periphery of the dummy head 41 is in a state where the pressing portion 46 is in contact with the peripheral portion of the cylinder bore 11. The bolt 16 and the nut 47 that are bolted to the block 12 function as pressing load state holding means. These dummy heads 41, bolts 16 and nuts 47 constitute pressing load means.

  Further, the honing apparatus 31 of this embodiment includes a rotating shaft 48 that can move in the vertical direction within the tool insertion hole 44, and a grindstone 49 is annularly arranged on the outer peripheral surface of the lower end portion of the rotating shaft 48. The honing head 50 is provided. In the present embodiment, the rotating shaft 48, the grindstone 49, and the honing head 50 constitute a honing means. Then, by rotating the rotating shaft 48 based on a rotational driving force from a driving source (not shown), the inner peripheral surface 11a of the cylinder bore 11 in the inner peripheral block 12 disposed at the honing position on the pedestal 33 is a perfect circle. Honed to be processed.

  Then, next, the method of honing the inner peripheral surface 11a of the cylinder bore 11 of the inner peripheral block 12 using the honing processing device 31 configured as described above, and the operation at that time will be described.

  Now, when performing the honing process, as shown in FIG. 3, the inner peripheral block 12 is first arranged in a state where the lower end surface of the cylinder liner portion 24 is in contact with the base 33 (the honing process position). The At this time, the piston 38 of the hydraulic cylinder 34 is in a position in which it is retracted into the cylinder body 36 by the urging force of the coil spring 37. Next, the dummy head 41 is placed on the upper deck portion 19 of the inner peripheral block 12 (that is, on the upper end surface 12 a of the inner peripheral block 12) with the pressing portion 46 in contact with the peripheral portion of the cylinder bore 11. . Then, the bolt 16 is inserted into the bolt insertion hole 45 of the flange portion 43 in the dummy head 41 and the bolt insertion hole 20 of the upper deck portion 19 in the inner peripheral block 12, and the nut 47 is screwed to the lower end portion of the bolt 16. That is, the dummy head 41 is assembled and fixed to the inner peripheral block 12 by bolt fastening based on the screwing of the nut 47.

  Then, a pressing load corresponding to a load applied when the cylinder head 14 is actually bolted with the cylinder head gasket 15 interposed from the dummy head 41 side to the upper end surface 12a of the inner peripheral block 12 due to the bolt fastening. Added. Therefore, the inner peripheral block 12 receives the pressing load, and the cylinder liner portion 24 (and the cylinder bore 11) is deformed from a perfect circle shape to a non-round shape. In this state, when hydraulic oil is supplied into the cylinder main body 36 of the hydraulic cylinder 34 via the pipe 35, the piston 38 advances by receiving the hydraulic pressure, and the support surface 40 is the lower end of the cylinder liner portion 24. The outer peripheral surface 25 of the part is pressed. That is, the support surface 40 of the piston 38 comes into surface contact with the outer peripheral surface 25 of the cylinder liner portion 24 deformed into a non-circular shape, and the outer peripheral surface 25 of the cylinder liner portion 24 is pressed and supported radially inward (see FIG. 5 (a)). Therefore, the support surface 40 of the piston 38 that comes into surface contact with the outer peripheral surface 25 of the cylinder liner portion 24 in a pressing support state is an arc surface whose pressing surface property (profile) follows a perfect circle shape in plan view. It is profiled in advance in a non-circular surface property along a non-circular shape, not a property.

  Then, in this state, the inner peripheral surface 11a of the cylinder bore 11 is honed into a perfect circle by a grindstone 49 provided on the honing head 50 based on the rotational drive of the rotary shaft 48 (see FIG. 5B). At that time, a pressing force from the grindstone 49 to the cylinder liner portion 24 radially outwards acts, but the outer peripheral surface 25 of the cylinder liner portion 24 is pressed and supported radially inward by the support surface 40 of the piston 38 in surface contact. Therefore, the cylinder liner portion 24 is not deformed by receiving the pressing force radially outward during the honing process. When the entire inner peripheral surface 11 a of the cylinder bore 11 is honed into a perfect circle by the grindstone 49, the hydraulic oil supply to the cylinder body 36 is stopped in the hydraulic cylinder 34.

  Then, the piston 38 is moved backward toward the cylinder body 36 by the biasing force of the coil spring 37, and the support surface 40 of the piston 38 is separated from the outer peripheral surface 25 of the cylinder liner portion 24. In parallel with this, the bolt 16 that has assembled and fixed the dummy head 41 to the upper end surface 12a of the inner peripheral block 12 is released from its bolt fastening state. Then, with the release of the bolt fastening state, the cylinder liner portion 24 (and the cylinder bore 11) of the inner peripheral block 12 is deformed so as to be restored to the original shape. That is, as shown in FIG. 6A, the portion that was deformed radially inward under the pressing load from the dummy head 41 was deformed radially outward and vice versa. The portion is deformed radially inward. Therefore, the inner peripheral surface 11a of the cylinder bore 11 honed into a perfect circle shape is deformed into a non-circular shape in cross section.

  Then, in a state where the inner peripheral block 12 after the honing process is inserted and assembled to the outer peripheral block 13, the cylinder head 14 has the cylinder head gasket 15 interposed on the upper end surface 12a of the inner peripheral block 12. It is assembled and fixed by bolt fastening in the state. Then, the load due to the bolt fastening at that time is applied in a state in which the surface pressure due to the cylinder head gasket 15 being interposed on the upper end surface 12a of the inner peripheral block 12 is added, and the cylinder liner portion 24 (and the cylinder bore 24) of the inner peripheral block 12 is added. 11) is deformed. That is, as indicated by a solid line in FIG. 6B, the inner peripheral surface 11a of the cylinder bore 11 that has become a non-circular shape due to the restoration is caused by the load accompanying the actual mounting and fixing of the cylinder head 14 as shown in FIG. As shown by a two-dot chain line in FIG. Therefore, the roundness of the cylinder bore 11 is ensured when the cylinder head 14 is assembled and fixed.

According to the honing method for the inner peripheral surface 11a of the cylinder bore 11 using the honing device 31 of the above embodiment, the following effects can be obtained.
(1) A pressing load corresponding to the load at the time of bolt tightening when the cylinder head gasket 15 is actually assembled and fixed with the cylinder head gasket 15 interposed is fixed by assembling and fixing the dummy head 41 on which the pressing portion 46 is formed. The inner peripheral surface 11a of the cylinder bore 11 is subjected to honing while being added to the peripheral block 12. That is, the inner peripheral surface 11a of the cylinder bore 11 is honed into a perfect circle under the same conditions as when the cylinder head 14 is actually mounted and fixed. Therefore, the roundness of the cylinder bore 11 is ensured well when the cylinder head 14 is assembled and fixed to the upper end surface 12a of the inner peripheral block 12 after the honing process with the cylinder head gasket 15 interposed. can do.

  (2) Further, at the time of honing, the outer peripheral surface 25 of the cylinder liner portion 24 that is easily distorted radially outward is pressed and supported radially inward by the support surface 40 of the piston 38 in a surface contact state. For this reason, honing is performed on the cylinder liner portion 24 (and the cylinder bore 11) that is held in a state where there is no unnecessary distortion and deformation, and the inner peripheral surface 11a of the cylinder bore 11 is honed to a perfect circle. Good processing accuracy is ensured. Therefore, when the cylinder head 14 is actually assembled and fixed, the roundness over the entire inner peripheral surface 11a of the cylinder bore 11 can be reliably improved.

  (3) The configuration for applying a pressing load corresponding to the load at the time of actual bolt tightening of the cylinder head 14 to the upper end surface 12a of the inner peripheral block 12 at the time of honing is equivalent to the cylinder head gasket 15. It is a simple one composed of a dummy head 41 or the like having a pressing portion 46 to be operated. Therefore, the inner peripheral surface 11a of the cylinder bore 11 can be honed into a perfect circle as desired while reducing the costs associated with the honing device 31 and the honing operation.

  (4) In addition, the configuration for improving machining accuracy when honing the inner peripheral surface 11a of the cylinder bore 11 is deformed into a non-circular shape under a bolt fastening load (= pressing load). The cylinder liner 24 is provided with a piston 38 having a surface-shaped support surface 40 corresponding to the outer peripheral surface of the cylinder liner portion 24. Therefore, the roundness over the entire inner peripheral surface 11a of the cylinder bore 11 can be reliably improved while reducing the costs associated with the honing apparatus 31 and the honing process.

  (5) Further, when honing the inner peripheral surface 11a of the cylinder bore 11, only the inner peripheral block 12 has to be disposed on the pedestal 33 that is the honing position, so that the apparatus configuration is reduced in size and scale. It is possible to reduce the apparatus cost related to the honing process.

  (6) In addition, since the dummy head 41 serving as a pressing load member is configured to apply a pressing load downward with the pressing portion 46 in contact with the upper end surface 12a of the inner peripheral block 12, an open deck structure and It can be applied to any type of cylinder block with a closed deck structure.

In addition, you may change the said embodiment into another embodiment (another example) as follows.
In the above embodiment, the inner peripheral surface 11 a of the cylinder bore 11 in the cylinder block 10 having a so-called closed deck structure in which the water jacket 17 is closed on the upper surface side by the upper deck portion 19 of the inner peripheral block 12 is honed. However, the lower end portion of the cylinder liner portion 24 of the inner peripheral block 12 is a cylinder block integrally joined to the lower end portion of the cylinder outer wall portion 29 of the outer peripheral block 13, and the inner peripheral surface of the cylinder bore in the open deck structure cylinder block is honed. It may be processed. In that case, a pressing load is applied in a state where the pressing portion 46 of the dummy head 41 is in contact with the upper end surface of the cylinder liner portion constituting the peripheral wall of the cylinder bore, and the diameter of the piston 38 with respect to the outer peripheral surface of the cylinder liner portion is increased. No pressing support is performed inward in the direction.

  In the above embodiment, the number of pistons 38 (and the hydraulic cylinders 34) that press and support the outer peripheral surface 25 of the cylinder liner portion 24 radially inward can be changed to any number as necessary.

  In the above embodiment, the hydraulic cylinder 34 that functions as a pressing support means is not necessarily provided. Further, the pressure support means may be constituted by another hydraulic cylinder such as a pneumatic cylinder in place of the hydraulic cylinder 34.

  In the above embodiment, the dummy head 41 serving as a pressing load member can be applied with a pressing load corresponding to the load at the time of actual bolt fastening to the upper end surface 12a of the inner peripheral block 12 via the pressing portion 46. For example, it is not necessarily required to be assembled and fixed to the inner peripheral block 12 by bolt fastening using a pressing load state holding member composed of the bolt 16 and the nut 47. For example, the dummy head 41 may be pressed from above by a press device in a state where the pressing portion 46 is in contact with the upper end surface 12a of the inner peripheral block 12.

  In the above embodiment, the configuration of the pressing load means is replaced with a configuration including the dummy head 41, the bolt 16 and the nut 47, and is configured by a clamping member having a convex portion corresponding to the pressing portion 46, and this clamping member However, when the upper deck portion 19 of the inner peripheral block 12 is clamped, the pressing portion 46 may abut against the peripheral portion of the cylinder bore 11.

(A) is a perspective view of a split-type cylinder block, (b) is the front view. FIG. 2 is a cross-sectional view taken along line AA in FIG. Schematic cross-sectional explanatory drawing of a honing processing apparatus. FIG. 4 is a partial cross-sectional view taken along line B-B in FIG. 3. (A) is sectional drawing explaining the cross-sectional shape of the cylinder bore inner peripheral surface before a honing process start, (b) is sectional drawing explaining the cross-sectional shape of the cylinder bore inner peripheral surface at the time of completion | finish of a honing process. (A) is sectional drawing explaining the cross-sectional shape of the cylinder bore inner peripheral surface after cancellation | release of a press load state and a press support state, (b) is a top view explaining the deformation | transformation state of a cylinder bore accompanying the assembly fixing of a cylinder head.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Split type cylinder block, 11 ... Cylinder bore, 11a ... Inner peripheral surface of cylinder bore, 12 ... Inner peripheral block, 12a ... Upper end surface, 13 ... Outer peripheral block, 14 ... Cylinder head, 15 ... Cylinder head gasket, 16 ... Bolt ( Pressure load state holding member), 19 ... upper deck part, 24 ... cylinder liner part, 25 ... outer peripheral surface of cylinder liner part, 29 ... cylinder outer wall part, 31 ... honing device, 34 ... hydraulic cylinder (press support means), 35 ... Piping (pressing support state holding member), 36 ... Cylinder body (pressing support state holding member), 38 ... Piston (pressing support member), 40 ... Support surface, 41 ... Dummy head (pressing load means, pressing load member), 46 ... Pressing part, 47 ... Nut (pressing load state holding member).

Claims (7)

When honing is performed on the inner peripheral surface of the cylinder bore formed in the cylinder block, the cylinder head is assembled and fixed on the cylinder block by bolt fastening with a cylinder head gasket interposed along the periphery of the cylinder bore. In this state, a pressing load corresponding to the load applied to the upper end surface of the cylinder block is applied to the upper end surface of the cylinder block arranged at the honing position, and in this state, the entire inner peripheral surface of the cylinder bore has a cross-sectional shape of the cylinder bore. A honing method for the inner peripheral surface of a cylinder bore that is honed so as to have a perfect circular shape. 2. The cylinder bore inner peripheral surface according to claim 1, wherein when performing the honing process, an outer peripheral surface of a cylinder liner portion which is a peripheral wall of the cylinder bore in the cylinder block is supported with a pressing load inward in the radial direction. Honing method. In the honing apparatus for the cylinder bore inner peripheral surface for honing the inner peripheral surface of the cylinder bore formed in the cylinder block,
The cylinder head on the cylinder block is honed to a pressing load equivalent to the load applied to the upper end surface of the cylinder block when the cylinder head gasket is assembled and fixed by bolt fastening in a state where the cylinder head gasket is disposed along the periphery of the cylinder bore. A pressing load means for applying to the upper end surface of the cylinder block arranged at a position;
Cylinder bore provided with honing means for honing the entire inner peripheral surface of the cylinder bore so that the cross-sectional shape of the cylinder bore becomes a perfect circle when the pressing load is applied to the upper end surface of the cylinder block by the pressing load means. Honing machine for inner surface. The pressing load means includes a pressing load member having a convex pressing portion whose cross-sectional shape corresponds to the cylinder head gasket, and the pressing load member contacts the peripheral portion of the cylinder bore in the upper end surface of the cylinder block. The honing apparatus for a cylinder bore inner peripheral surface according to claim 3, further comprising a pressing load state holding member that is in contact with and holds the cylinder block in a state where a pressing load corresponding to the load is applied to the upper end surface of the cylinder block. 5. The inside of the cylinder bore according to claim 3, further comprising pressing support means for pressing and supporting the outer peripheral surface of the cylinder liner portion serving as a peripheral wall of the cylinder bore in the cylinder block with a pressing load inward in the radial direction. Perimeter honing machine. The pressing support means includes a pressing support member having a surface-shaped supporting surface corresponding to an outer peripheral surface of a cylinder liner portion in a cylinder block in a state where the pressing load is applied to an upper end surface by the pressing load means, and the pressing support member And a pressing support state holding member for holding the supporting member in a state where the supporting surface comes into surface contact with the outer peripheral surface of the cylinder liner portion and presses and supports the outer peripheral surface of the cylinder liner portion radially inward. Item 6. A honing apparatus for an inner peripheral surface of a cylinder bore according to Item 5. The cylinder block is divided into an inner peripheral block formed with an upper deck portion for mounting and supporting the cylinder head, and an outer peripheral block formed with a cylinder outer wall portion into which the inner peripheral block is inserted and assembled from above. And the honing processing apparatus of the cylinder bore inner peripheral surface as described in any one of Claims 3-6 by which only an inner peripheral block is arrange | positioned in the said honing processing position at the time of honing processing.

Images