JP4464785B2 - Manufacturing method of honing head and honing head main body - Google Patents

Description

  The present invention relates to a honing head for grinding a cylindrical hole or an inner surface of a hole.

  When a cylindrical hole or hole is required for an object made of metal, the object body and the hole or hole are integrated by casting, or a solid material is processed and formed using a cutting tool such as a drill or a bite. However, the machining accuracy that can be provided by the cutting tool is not high, and when precise fitting or contact sliding is required, a higher precision finish is required for the hole or hole. This requirement is met using a grinding tool equipped with a grindstone called a honing head. Normally, a grinding tool is a dedicated product prepared for each hole or hole diameter, and the range in which one tool can be machined is smaller than other tools.

A grinding tool called a honing head is provided with a plurality of slits penetrating from the center of the cylinder to the outer peripheral surface, and a grindstone with a grindstone is inserted. An adjustment shaft with a cone that slides on the bottom surface of the grinding wheel table and the center of the cylinder is brought into contact, and the movement of the shaft is changed to a movement in the radial direction, which is transmitted to the grinding wheel and the other party is ground. The grindstone table is provided with means for preventing unnecessary movement during grinding and dropping off when the grindstone is separated from the workpiece. [Patent Document 1] discloses a means for urging centripetal force to a grindstone table using an O-ring or a spring ring, and [Patent Document 2] discloses a restraining means for providing a groove between the grindstone table and a conical shaft.
JP 54-119192 A Shokai 58-44160

  The structure of the honing head shown in FIG. 1 of Patent Document 1 applies a ring-shaped tension spring to both ends of a plurality of grindstone heads with a grindstone, and urges and restrains a force toward the center. In this structure, both ends of the grindstone are occupied by the tension springs, so that the effective length of the grindstone is reduced, and the position of the tension spring at the tip is an obstacle to the grinding of the corners such as the hole bottom. As shown in FIGS. 5 and 6, Patent Document 2 has a structure in which a groove is provided between the wheel head and the pyramid to prevent it from coming off, but this structure has a processing accuracy in each shape of the slit, the wheel head and the pyramid. Since it is entangled, it takes time to adjust the assembly during production.

  In both documents, the movement of the adjusting shaft is transmitted to the grindstone via the slope of the grindstone head, but a structure is adopted in which the movement amount in the radial direction of all the grindstone heads is the same. This structure is unlikely to cause problems if the surface roughness accuracy is μ level above the decimal point, but if a μ level below the decimal point is required, the required accuracy is required for a honing head with a rigid structure that does not have elasticity in the movement of the grindstone. This raises the problem that it will be difficult to realize. This cause is related to the fact that the cylindrical hole or hole cut in the object to be ground is not a perfect circle.

  As shown in FIG. 1 of the present invention, when a hole or hole cut by a tool or a drill and a longitudinal section are schematically drawn, the diameter can be expressed as an ellipse with X axis = D and Y axis = D ′ (D> D ′). . When this state is ground by a grinding allowance δ in the X-axis direction using a honing head having a rigid structure with a grindstone outer diameter d, the diameter as shown in FIGS. Grinding allowances for the XY axes of the surface height (roughness) H at the time of cutting D and D ′ are δ and δ ′, and there is a difference in the area of the valley portion as shown by the oblique lines. When this state is applied to the cylinder bore wall surface of the engine, a difference occurs in the oil retaining state, which is not preferable for lubrication between the cylinder and the piston.

When grinding a non-circular hole or hole with a rigid honing head, within a large tolerance range, a large number of ground workpieces that fall within the tolerance range can be grouped by dividing the tolerance range. It becomes possible. Since the grouped workpieces have the advantage of expanding the choices of combinations when mating with the counterpart, the treatment is widely used for the combination of parts that require mating, but it is not preferable from the viewpoint of cost. Absent. Accordingly, a means for advancing the assembly by narrowing and narrowing the allowable tolerance range and narrowing the options of fitting has been tried, but it is difficult to realize due to the structural problem of the grinding tool.

  As a result of studying the movement of the grinding wheel head in the honing head, the present applicant gives elasticity to the grinding wheel base so that each grinding wheel base can be independently deformed separately from the radial movement transmitted from the adjusting shaft. We have developed a structure and succeeded in giving the grindstone a flexible function that moves according to the surface condition of the workpiece. In addition, as a result of easy slitting of the head body and effective utilization of the tip of the grinding wheel, the synergistic effect with the elasticity of the grinding wheel itself has been improved, and a flexible structure capable of high-precision grinding that solves the problems described above Successfully provided a honing head.

The present invention of claim 1 is provided with at least one slit (22) penetrating from the inner surface to the outer surface of the head body (21), and inserting a grindstone base (4) with a grindstone (3) into the slit, A moving means for sliding the grinding wheel base (4) along the inner wall of the slit (22) is incorporated, and further, a slit (6, 8) is placed near the grinding wheel mounting surface (5) of the grinding wheel base (4). In the honing head, the slit (6, 8) is reversed along the mounting surface through a direction perpendicular to the grinding wheel mounting surface (5), starting from the rear end of the grinding wheel mounting surface (5). The beam (11) formed on the grinding wheel head (4) is in a cantilever shape with a fulcrum (9) placed near the front end in the direction opposite to the starting point. It is characterized by being.
  The present invention of claim 2 is provided with at least one slit (22) penetrating from the inner surface to the outer surface of the head body (21), and inserting a grindstone base (37) with a grindstone (36) into the slit, A honing head having a built-in moving means for sliding the grinding wheel base (37) along the inner wall of the slit and further inserting a slit (39, 40) near the grinding wheel mounting surface (38) of the grinding wheel base (37). In this case, two slits (39, 40) are formed on the grindstone mounting surface (38) with the common fulcrum (41) being sandwiched between them, thereby forming a beam ( 42, 43) is in the shape of a cantilever with the common fulcrum (41) placed in the middle of the grinding wheel platform (37).
The present invention of claim 3 further comprises a slot (44) formed along the grinding wheel mounting surface (38) according to the invention of claim 2, whereby the grinding wheel platform (37). The beam (46) formed in the above is a doubly supported beam shape with both ends (45) of the grinding wheel platform (37) as fulcrums.

The effects obtained from the honing head of the present invention will be listed.
1) The grindstone head with elasticity is deformed according to the surface condition of the work piece and is not ground excessively. When a plurality of grindstone heads are used, each grindstone table is deformed corresponding to the surface state of the object to be ground to give a preferable grinding result.
2) The grindstone head with elasticity made it possible to raise the roughness accuracy of the surface of the workpiece to the μ level below the decimal point compared to the conventional grindstone head with rigid structure.
3) When a grinding wheel rich in elasticity and a grinding wheel head with elasticity are combined, a favorable synergistic effect is obtained for grinding (polishing).
4) The method of this application that forms the slit of the head body with the processed fork and ring is easier to process and secures the required accuracy compared to the conventional method that requires labor to open from the radial direction. This contributed to lowering the production cost of the honing head.
5) A structure that allows the front end of the wheel head to be bound by an O-ring at a position that does not hinder assembly without impairing the overall length of the wheel and the effective use of the tip.

  The engine cylinder bore described above can be given as one of the typical objects to be ground that requires honing. Conventionally, the surface roughness accuracy required for cylinder bores has been at the micron level above the decimal point, but since the progress of technological development has begun to require the micron level below the decimal point, in the present invention, a rigid grinding wheel head is used. Instead, a flexible whetstone stand with elasticity was used for the honing head to meet the requirements.

  The elasticity required for the grinding wheel base is that when the grinding wheel comes into contact with the surface of the object to be ground, it reacts and deforms in response to the strength of the contact pressure transmitted from the surface of the object to be ground to the grinding wheel. And preferably, it exhibits the same degree of elasticity over the entire length of the grindstone. For this purpose, when the grindstone is provided with a slot, at least one cantilever is formed on the grindstone to provide elasticity, and when two or more cantilevers are used, the movement of each cantilever Arranged to produce a synergistic effect.

The deflection of the cantilever beam is determined by the load, the elastic modulus of the material used, the length from the fulcrum and the cross-sectional area, and the deflection amount of the beam varies depending on the position and size of the load. However, it is desirable that the grinding wheel base can obtain nearly uniform elasticity and bending over the entire length of the grinding wheel. Therefore, when two cantilever beams are overlapped to form a two-stage structure, a structure is obtained in which the movements of both beams influence each other and respond to minute changes in surface pressure. The combination may be a cantilever beam and a cantilever beam, and the laminated structure is not limited to double. The way of slitting is along the wheel mounting surface from the end of the wheel head, stopping just before reaching the other end, and the remaining part becomes a cantilever, and the rear of the wheel mounting surface is cut vertically and mounted together If a reverse L-shape is drawn along the surface, it becomes a cantilever beam in the reverse direction.

  The slitting dimensions of the wheel head were selected from the following numerical range. The length is selected from the range of 0.60 to 0.95, preferably 0.70 to 0.95, and more preferably 0.80 to 0.95. The calculated value is multiplied by the grinding wheel length. In the second and subsequent slots, the total length in the horizontal direction is selected from the above range. The numerical value is determined in consideration of the workpiece and the grinding wheel length that requires elasticity. The direction is parallel to the grindstone or with a small angle, and the width takes into account the elasticity of the beam.

  The slit provided in the head body was formed by cutting a required length from a cylindrical end surface perpendicular to the axis toward the other end to form a fork, and inserting and fixing a ring at the open end of the fork. Compared to a slit that opens from the cylindrical surface toward the center in the radial direction, this process opens up one side of the slit, expanding the options for the type and size of the cutting tool, increasing production speed and ensuring accuracy. The effect to say is acquired.

  The position where the grinding wheel base is fixed to the head body with an O-ring or ring-shaped coil spring does not reduce the effective length of the grinding wheel, does not hinder the use of the grinding wheel tip, and does not hinder the assembly work of the honing head. did. For this reason, a part of the grindstone table was pushed out to the outside of the ring forming one side of the slit, and the mounting position of the O-ring or ring-shaped coil spring at the front end of the grindstone table was set inside the ring.

  FIG. 1 is a model diagram showing the relationship between a honing target cutting hole (including a hole) and a rigid honing head. 2A and 2B are model diagrams of hole cross sections showing the surface states at points D and D 'in FIG. 3A and 3B are a front view of the honing head and a side view including a partial cross-section along the line aa in FIG. FIG. 4 is an exploded perspective view of FIG. 5A, 5B, and 5C are a front view, a side view, and a plan view of a grindstone table in which cantilever beams are arranged in two stages. FIG. 6 is a perspective view of the head body fitted with a ring. FIGS. 7A and 7B are elastic action diagrams of a grindstone head with a grindstone.

  As described in FIG. 1 and FIG. 2 (A, B, C) in the previous [0006] section, there is no cylindrical hole or hole processed into a perfect circle. It is difficult to finish this cylindrical hole or hole with a rigid honing head to a uniform surface roughness, and it becomes more difficult if the surface roughness accuracy of grinding is increased. For this solution, a honing head having a flexible structure based on an idea different from the conventional one is required. In the present embodiment, a honing head in which a problem is solved by adding a flexible movement (elasticity) by slitting a grindstone table.

  As shown in FIGS. 3 (A, B), 4 and 5 (A, B, C), the honing head has an inclined surface 30 of the adjusting shaft 29 that slides in the center of the head body 21 to cause the grinding wheel base 2 with a grinding wheel to have a radius. Move in the direction. Although this structure itself is the same as the conventional one, in the present invention, a linear slot 6 having a width of 0.3 mm and an inverted L-shaped slot 8 are arranged on a grindstone, and a fulcrum formed at the end of the slot. Two cantilever beams 10 and 11 that move around 7 and 9 were formed on the grinding wheel base to give elasticity. The first cantilever is supported by the second cantilever so that flexibility is added to both movements.

The grindstone 3 is attached to the grindstone base 4, and the outer peripheral surface of the head main body 21 is equally divided and inserted into six slits 22 arranged in the radial direction. When the grindstone platform completely fits in the slit, the tip 12 of the first cantilever was placed on the outer peripheral surface 29 of the ring 28 described later forming one side of the slit. The means for engaging the grindstone head and the head main body is provided with a front O-ring groove 13 on the lower side of the front end face of the grindstone table and a rear O-ring groove 14 on the rear end of the grindstone mounting surface 5, and an O-ring in each groove. 19 and 20 were inserted, and the centripetal force was applied to the grinding wheel head with the grinding wheel.

  FIG. 6 is a completed view of the head main body 21. In the slit 22, a hole 23 for the adjustment shaft 29 is formed in the cylindrical head body and a ring mounting seat 24 is processed on the front end surface, and a length necessary for forming the slit is cut from the front end surface toward the other end in the axial direction. A thick fork 25 is formed. In the procedure of press-fitting the ring 26 into the ring mounting seat at the open end of the fork, a slit is formed by three sides of the fork and one side of the ring. Therefore, the means for closing the ring with the ring after molding the fork after forming the fork in the radial direction from the outer peripheral surface of the cylinder can be easily processed with a wide range of types and sizes of processing tools.

  The operation of the grindstone head 2 with a grindstone provided with the two slits 6 and 8 shown in FIGS. 7A and 7B will be described with reference to FIG. When grinding a non-circular cylindrical hole or hole, if the cutting surface height (roughness) H is ground with a rigid honing head, the grinding allowances δ and δ ′ of each XY axis can be made equal. Although it is difficult, when the grinding wheel head with elasticity according to the present invention is used, if excessive surface pressure is applied to the grinding wheel surface of the Y axis during the grinding process, the grinding wheel base is deformed or retracted, so that the grinding amount can be suppressed. Grinding is performed. Accordingly, the grinding allowance for each of the XY axes approaches as much as possible.

  The function is that the two-stage cantilever beams 10 and 11 are formed on the grindstone base 4. In this structure, when the same external force P is applied to the left end 15 or the right end 16 of the grindstone, both are provided with the bending and elasticity shown by the dotted line. When the point of action of the external force moves from the end to the inside, the movement of the two cantilevers increases the degree of correlation and a synergistic effect is obtained. When grinding with such a honing head that moves flexibly, the grinding allowance of the surface of a cylindrical hole or hole that is not a perfect circle can be concentrated to δ, and the surface roughness accuracy can be finely and evenly finished.

  After the push rod 31 is fixed to the adjustment shaft 29 that slides in the center of the head main body 21, the push rod is first inserted into the hole 23 of the head main body, and after the insertion, the coil spring 29 is fitted and the coil spring is compressed. A collar 33 is fitted on the rear portion of the push rod and a retaining ring 34 is formed. When the honing head 1 is connected to a grinding machine (not shown), axial movement and rotation of the head body are transmitted to the push rod. Since the configuration of the latter half of the head main body is not different from the conventional one, the above description is omitted.

  In FIG. 8, along the grinding wheel mounting surface 38 of the grinding wheel base 37, slits 39, 40 are placed on the upper stage, cantilever beams 42, 43 having a common fulcrum 41 are arranged back to back, and the slit 44 is placed at the center of the lower stage. It is a grindstone table 35 with a grindstone that has a double structure by placing doubly-supported beams 46 having fulcrums 45 at both ends of the grindstone table. In this structure, when an external force is applied to the grindstone 36, the entire length provides bending and elasticity, and the action of the upper and lower beams also produces a synergistic effect, thereby providing a flexible movement as a whole. The strength of this movement is related to the material and dimensions of the beam, and the relationship between the elasticity and the slit width is the same as in the first embodiment.

It is a model figure which shows the relationship between the honing cutting hole (a hole is included) and the honing head of rigid structure. (A, B) is a model figure which shows the grinding state of the hole cross section of D and D 'point of FIG. (A, B) is a front view of a honing head and a side view including a partial cross section along the aa line of FIG. 3 (A). Example 1 FIG. 4 is an exploded perspective view of FIG. 3. (A, B, C) are a front view, a side view, and a plan view of a grindstone table in which two cantilevers are arranged. It is a perspective view of the head main body which fitted the ring. (A, B) is an elastic action diagram of a grinding wheel head with a grinding wheel. (Example 2) It has a double structure in which two cantilever beams are arranged back to back on the upper stage of the grinding wheel platform and both cantilevers are arranged on the lower stage.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Honing head 2,35 Grinding wheel stand with a grindstone 3,36 Grinding stone 4,37 Grinding stone stand 5,38 Grinding wheel mounting surface 6,8,39,40,44 Slot 7,9,41,45 Support point 10,11,42, 43 Cantilever 12 Tip 13, 14 O-ring groove 15, 16 Left end, right end 17, 30 Slope 19, 20 O-ring 21 Head body 22 Slit 24 Ring mounting seat 25 Fork 26 Ring 29 Adjustment shaft 31 Push rod 46 Double-supported beam

Claims (3)

At least one slit (22) is provided so as to penetrate from the inner surface to the outer surface of the head body (21), and a grindstone base (4) with a grindstone (3) is inserted into the slit (22). In the honing head, a moving means is slid along the inner wall of the slit (22), and a slit (6, 8) is inserted near the grindstone mounting surface (5) of the grindstone base (4). ,
The slit (6, 8) is placed in an inverted L shape along the mounting surface through a direction perpendicular to the grinding wheel mounting surface (5), starting from the rear end of the grinding wheel mounting surface (5). Is,
Accordingly , the honing head is characterized in that the beam (11) formed on the grindstone bed (4) has a cantilever shape with a fulcrum (9) placed near the front end in the direction opposite to the starting point . At least one slit (22) is provided so as to penetrate from the inner surface to the outer surface of the head body (21), and a grindstone base (37) with a grindstone (36) is inserted into the slit (22). In the honing head, which has a built-in moving means that slides along the inner wall of the slit, and further has a slit (39, 40) near the grindstone mounting surface (38) of the grindstone table (37),
  Two of the slits (39, 40) are formed across the common fulcrum (41) along the grinding wheel mounting surface (38),
Thereby, the beam (42, 43) formed on the grindstone bed (37) is in the form of a cantilever with the common fulcrum (41) placed in the middle of the grindstone bed (37). head. It further has one slit (44) formed along the grinding wheel mounting surface (38), so that the beam (46) formed on the grinding wheel platform (37) becomes the grinding wheel platform (37). The honing head according to claim 2, wherein the honing head has a doubly-supported beam shape with both ends (45) as fulcrums.