JP2004116414A - Valve seat press fitting device - Google Patents

Abstract

An object of the present invention is to provide a valve seat press-fitting device capable of suppressing a misalignment between a valve seat and a valve seat fitting hole, performing a smooth press-fitting operation of a valve seat, and improving productivity.
A holder body (11) that moves forward along a valve seat fitting hole (2) formed in a cylinder head (1) along a center axis (a) of a press-fit holder (10), and a tip holder supported by a tip (11a) of the holder body (11). 16, a collet 25 supported by the tip holder 16 and having a sheet holding portion at the tip, an intermediate shaft member 36, and a spring 48 for urging the center shaft member 36 toward the holder body 11. The diameter of the seat holding portion 28 is expanded by the urging of the center shaft member 36, and the valve seat 5 is fitted and held on the outer peripheral surface 30 of the seat holding portion 28 by the expanded diameter.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a valve seat press-fitting device for press-fitting a valve seat of an intake and exhaust valve of an engine into a cylinder head.
[0002]
[Prior art]
The valve seat of the intake / exhaust valve of the engine is assembled by being press-fitted into a stepped valve seat fitting hole formed in the cylinder head using a press-fitting device.
[0003]
After the engine is completed, a load acts in the axial direction of the valve seat and a large thermal load is applied to the press-fitting of the valve seat. Therefore, if the valve seat is not in close contact with the bottom of the valve seat fitting hole, it is in use. Of the valve seat, causing various adverse effects such as fluctuation of valve clearance and generation of noise, and it is required to securely press-fit the valve seat into the valve seat fitting hole.
[0004]
As a valve seat press-fitting device, for example, there is one having a structure shown in FIG. In this valve seat press-fitting device, a ring-shaped valve seat 5 at room temperature is press-fitted into a valve seat fitting hole 2 of the cylinder head 1 which has been heated to about 110 to 130 ° C. in advance. A plurality of steel balls 104 urged by a leaf spring 103 are incorporated in a seat holding portion 102 of the valve 101. When the valve seat 5 is inserted into the seat holding portion 102, a plurality of steel balls 104 urged by the leaf spring 103 are applied. The valve seat 5 is held by the steel ball 104 so as not to fall off.
[0005]
When the press-fit holder 101 holding the valve seat 5 in advance in this way is advanced by a hydraulic cylinder or the like (not shown), the guide pins 105 provided on the press-fit holder 101 are inserted into the guide holes 4 of the valve guide 3, and Guided by the guide hole 4, the press-fit holder 101 advances, and the valve seat 5 is pressed into the valve seat fitting hole 2. Here, the manufacturing tolerance of the inner diameter of the valve seat 5 is relatively large (approximately ± 0.2 mm), and the outer diameter of the seat holding portion 102 is set according to the small inner diameter of the valve seat 5.
[0006]
FIG. 7 shows another valve seat press-fitting device. This valve seat press-fitting device pushes the valve seat 5 into a valve seat fitting hole 2 formed in the cylinder head 1 by advancing a press-fit holder 111 on which the valve seat 5 is supported. A floating holder 113 floatingly supported at the tip of the main body 112, an air chamber 114 for urging the floating holder 113 in a direction away from the holder main body 112, and the floating holder 113 in a radial neutral position with respect to the holder main body 112. A plurality of ball plunger units 115 to be held, and a lever 122 rotatably mounted via a hinge pin 122 a in a lever accommodating groove 121 formed at the tip of the floating holder 113. Litter in force Sheet holding portion 120 having a spring 112b is disposed.
[0007]
The ball plunger unit 115 includes a ball 115a and a spring 115b for urging the ball 115a against a support shaft 117 attached to the floating holder 113, as shown in FIG. A plurality of ball plunger units 115 are arranged at equal positions in the circumferential direction on a cap 116 attached to the holder main body 112.
[0008]
When the valve seat 5 is mounted on the seat holding portion 120, the lever 122 comes into close contact with the bottom of the lever accommodating groove 121 against the return spring 122b, and the return spring 122b pushes the lever 122 against the inner peripheral surface of the valve seat 5. The valve seat 5 is held by the seat holding portion 120 by being urged.
[0009]
When the press-fit holder 111 advances while the valve seat 5 is mounted, the guide pin 125 at the tip of the floating holder 113 is inserted into the guide hole 4 of the valve guide 3 of the cylinder head 1, and the guide pin 125 and the valve guide 3 When the floating holder 113 moves forward and the valve seat 5 starts to come into contact with the opening edge of the valve seat fitting hole 2, if the axes of the two are completely coincident with each other, the valve seat 5 is left as it is. 5 is press-fitted into the valve seat fitting hole 2, but if there is a misalignment between the two, the floating holder 113 urged by the ball plunger unit 115 moves in the radial direction to absorb the misalignment. Then, the valve seat 5 is pressed into the valve seat fitting hole 2 (for example, see Patent Document 1).
[0010]
[Patent Document 1]
JP-A-11-10456 (paragraph numbers 0039 to 0005, 0025 to 0032, 0039 to 0040, FIGS. 1, 2, and 6)
[0011]
[Problems to be solved by the invention]
According to the valve seat press-fitting device shown in FIG. 6 described above, the valve seat 5 is held on the seat holding unit 102 by the plurality of steel balls 104 that are spring-biased by the leaf springs 103 provided on the seat holding unit 102.
[0012]
However, the valve seat fitting hole 2 and the valve seat 5 of the cylinder head 1 are chamfered to facilitate the insertion of the valve seat 5, respectively. The allowable amount of misalignment with the valve seat 5 is small, for example, 0.5 mm or less. Here, as described above, since the outer diameter of the seat holding portion 102 is set in accordance with a small inner diameter manufacturing error of the valve seat 5, a valve seat having a large inner diameter has been produced due to manufacturing tolerance. In this case, the clearance (play) between the inner diameter of the valve seat 5 and the outer diameter of the seat holding portion 102 becomes large, and the valve has a misalignment between the seat holding portion 102 and the valve seat 5 due to the clearance. When the seat 5 is held, misalignment between the valve seat 5 and the valve seat fitting hole 2 occurs, and when the valve seat is press-fitted, the valve seat 5 and the valve seat fitting hole 2 are excessively abutted to cause galling or the like. The work of press-fitting the valve seat is hindered, and the work of press-fitting the valve seat and the smooth removal of the seat holding portion 102 from the valve seat 5 after the press-fitting are hindered. It is a concern affect.
[0013]
According to the valve seat press-fitting device shown in FIGS. 7 and 8, the lever 122 is pressed against the inner peripheral surface of the valve seat 5 fitted in the seat holding portion 120 to hold the valve seat 5 in the seat holding portion 120. Therefore, a misalignment occurs between the seat holding unit 120 and the valve seat 5 held by the seat holding unit 120.
[0014]
In addition, since the floating holder 113 is held at the neutral position in the radial direction by the plurality of ball plunger units 115, the holder main body 112 and the floating holder 113 are displaced due to an imbalance in the mounting position of each case 115c or an imbalance in the urging force of the spring 115b. The misalignment may occur between the valve seats 113, and the misalignment may be induced between the valve seat 5 and the valve seat fitting hole 2 due to the misalignment, thereby hindering smooth press-fitting of the valve seat. There is a concern that productivity may be reduced.
[0015]
Accordingly, an object of the present invention, which has been made in view of such a point, is to suppress the misalignment between the valve seat and the valve seat fitting hole, to obtain a smooth press-fitting operation of the valve seat, and to expect an improvement in productivity. It is to provide a valve seat press-fitting device.
[0016]
[Means for Solving the Problems]
The invention of the valve seat press-fitting device according to claim 1 which achieves the above object is characterized in that the valve seat is held by a press-in holder, and the press-in holder is advanced to a valve seat fitting hole formed in a cylinder head. In a valve seat press-fitting device for press-fitting a valve seat into a valve seat fitting hole, the press-fit holder is configured to move forward with respect to a valve seat fitting hole formed in the cylinder head along a central axis of the press-fit holder. A main body, a tip holder supported by the tip of the holder body, and a substantially cylindrical body supported by the tip holder and protruding from the tip of the tip holder to form a sheet holding portion and having a central shaft member insertion hole formed therein. And a collet having a plurality of slits for dividing the sheet holding portion into a plurality at equal intervals in the circumferential direction, and penetrating through the center shaft member insertion hole. And a biasing means for biasing the central shaft member toward the holder body, and biasing the central shaft member toward the holder body by the biasing means. The diameter of the seat holding portion is increased by the above, and the valve seat is fitted and held on the outer periphery of the seat holding portion by the increased diameter.
[0017]
According to the first aspect of the present invention, the diameter of the seat holding portion of the collet is enlarged by the central shaft member, and the valve seat is fitted and held on the outer periphery thereof. The valve seat is held in a state in which there is no clearance between the inner peripheral surface and the inner peripheral surface, and the occurrence of misalignment with respect to the seat holding portion is avoided or extremely suppressed. Therefore, the valve seat can be press-fitted into the valve seat fitting hole of the cylinder head in a state where the misalignment between the valve seat and the valve seat fitting hole is suppressed. An improvement in productivity can be expected.
[0018]
According to a second aspect of the present invention, in the valve seat press-fitting device of the first aspect, the centering of the seat holding portion on the center axis of the center shaft member with the biasing of the center shaft member toward the holder body side. It is characterized by having a mechanism.
[0019]
According to the second aspect of the invention, the misalignment between the center shaft member and the seat holding portion of the collet is suppressed, and the misalignment between the valve seat and the valve seat fitting hole is suppressed, and the valve seat is moved to the valve seat of the cylinder head. It can be pressed into the fitting hole.
[0020]
According to a third aspect of the present invention, in the valve seat press-fitting device according to the first or second aspect, the diameter of the collet is increased as the collet continues to the distal end of the center shaft member insertion hole and moves toward the distal end side in the seat holding portion. An inner peripheral surface having a substantially conical tapered surface centering on the center axis of the collet to be formed is provided. The diameter increases as the distal end of the central shaft member moves toward the distal end, and abuts against the inner peripheral surface of the collet. It is characterized in that it has a tip portion having an outer peripheral surface having a substantially conical tapered surface shape centered on the central axis of the central shaft member.
[0021]
According to the third aspect of the present invention, when the valve seat is pressed against the seat holding portion, the seat holding portion is pushed out by the inner peripheral surface thereof against the urging means so as to extrude the distal end portion of the central shaft member to reduce the diameter of the valve seat. The outer peripheral surface formed at the front end of the central shaft member can be pressed against the inner peripheral surface of the collet by pressing the central shaft member in the axial direction, and the sheet retaining portion can be expanded. The valve seat is diametrically adhered to the inner peripheral surface of the valve seat, and the seat holding portion is centered on the center axis of the center shaft member, thereby suppressing the occurrence of misalignment of the portion and stably holding the valve seat. .
[0022]
According to a fourth aspect of the present invention, in the valve seat press-fitting device according to the third aspect, an outer peripheral surface of the distal end portion has a substantially spherical shape having a center axis of the center shaft member as an axis.
[0023]
According to the fourth aspect of the present invention, the outer peripheral surface formed at the distal end portion of the center shaft member has the tapered inner peripheral surface of the collet abutting in a ring shape over the entire circumference, so that the sheet holding portion is entirely rotated. , The occurrence of misalignment of the seat holding portion can be more reliably suppressed, and the misalignment of the valve seat can be avoided.
[0024]
According to a fifth aspect of the present invention, in the valve seat press-fitting device of the third or fourth aspect, an intersection angle between a center axis of the collet and the inner peripheral surface is in a range of 25 ° to 45 °. .
[0025]
The invention of claim 5 is a more specific limitation of the invention of claim 3 or 4, wherein the intersection angle between the central axis of the collet and the inner peripheral surface is set in a range of 25 ° to 45 °. As a result, the diameter of the seat holding portion is reduced by pressing the seat holding portion against the seat valve. As a result, the valve seat can be easily held, and the displacement of the center of the seat holding portion due to the pressing of the outer peripheral surface of the front end portion of the central shaft member can be suppressed.
[0026]
According to a sixth aspect of the present invention, in the valve seat press-fitting device according to any one of the first to fifth aspects, the center shaft member is held by the tip holder so as to be movable coaxially with the center axis of the press-fit holder. It is characterized by the following.
[0027]
According to the invention of claim 6, by holding the center shaft member movably coaxially with the center axis of the press-fit holder, the valve seat can be held on the center axis in a state where the misalignment is suppressed, The valve seat can be pressed into the valve seat fitting hole of the cylinder head in a state where the misalignment between the valve seat and the valve seat fitting hole is suppressed.
[0028]
According to a seventh aspect of the present invention, in the valve seat press-fitting device according to any one of the first to fifth aspects, the center shaft member is inserted with a clearance into a center shaft member insertion hole formed in the tip end holder. In addition, it is characterized by being floating supported by an annular elastic member interposed between the center shaft member insertion hole and the center shaft member.
[0029]
According to the invention of claim 7, the center shaft member is floatingly supported by the distal end holder in a state where the center shaft member is centripetally biased on the center axis line, and the valve seat and the valve seat fitting hole are held by the seat holding portion. The valve seat can be smoothly pressed into the valve seat fitting hole even when there is a slight misalignment therebetween.
[0030]
According to an eighth aspect of the present invention, in the valve seat press-fitting device according to any one of the first to fifth aspects, the tip holder has a columnar mounting portion extending to a base end side of the tip holder. The device is characterized in that it is inserted with a clearance into a mounting hole formed in the main body, and is floating supported by an annular elastic member interposed between the mounting member and the mounting hole.
[0031]
According to the eighth aspect of the present invention, the distal end holder is floatingly supported by the holder body in a state where the distal end holder is eccentrically biased on the central axis line by the elastic member, and is between the valve seat held by the seat holding portion and the valve seat fitting hole. Even when there is a slight misalignment, the valve seat can be smoothly pressed into the valve seat fitting hole.
[0032]
According to a ninth aspect of the present invention, in the valve seat press-fitting device according to the seventh or eighth aspect, the valve guide is provided on the cylinder head so as to protrude coaxially with the center axis of the center shaft member at an end of the center shaft member. A guide pin that can be fitted into the device.
[0033]
According to the ninth aspect of the present invention, the guide pin is provided at the tip of the central shaft member so as to be fitted into the valve guide, so that the valve seal is guided and guided by the valve guide so that the valve seal can be press-fitted. .
[0034]
According to a tenth aspect of the present invention, in the valve seat press-fitting device according to any one of the first to ninth aspects, a stopper for regulating movement of the center shaft member is provided between the center shaft member and the tip holder. It is characterized by the following.
[0035]
According to the tenth aspect of the present invention, the amount of diameter expansion of the seat holding portion of the collet that holds the valve seat is set by disposing a stopper that restricts the movement of the center shaft member between the center shaft member and the tip holder. be able to.
[0036]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a valve seat press-fitting device according to the present invention will be described with reference to the drawings.
[0037]
(1st Embodiment)
1 to 3 show a first embodiment of a valve seat press-fitting device according to the present invention. FIG. 1 is a sectional view showing an outline of the valve seat press-fitting device, and FIG. 2 is an enlarged view of a portion A in FIG. FIG. 3 is a sectional view taken along line II of FIG.
[0038]
The valve seat press-fitting device according to the present embodiment, for example, moves the part between the part delivery unit in which the press-fit holder 10 houses the valve seat 5 and the work position where the valve seat 5 is attached to the cylinder head 1 of the engine, and transfers the parts. The valve seat 5 held by the part is cooled to a normal temperature state or, for example, about -100 ° C. with respect to the valve seat fitting hole 2 on the cylinder head 1 side previously heated to about 110 to 130 ° C. in the working position. The ring-shaped valve seat 5 in the state is press-fitted.
[0039]
The press-fit holder 10 includes a holder main body 11 and a valve seat holding portion 15 attached to a tip of the holder main body 11.
[0040]
The holder main body 11 is driven forward and backward by a hydraulic cylinder or the like (not shown) along the center axis a of the press-fit holder 10 at the parts transfer portion and the working position. A cylindrical mounting hole 12 having a center axis a as an axis is formed in a tip 11 a of the holder body 11.
[0041]
On the other hand, the valve seat holding portion 15 is supported by the tip member 21, which includes an intermediate holder 17 attached to the attachment hole 12 of the holder body 11 and a substantially cylindrical tip member 21 attached to the intermediate holder 17. A collet 25 for holding the valve seat 5, a central shaft member 36 for expanding the diameter of the collet 25, a spring receiver 42 provided at the base end of the central shaft member 36, and a space between the distal member 21 and the spring receiver 42. A spring 48 that is elastically mounted and biases the center shaft member 36 toward the holder body 11 is a main component.
[0042]
The intermediate holder 17 has a bottomed cylindrical base 18 formed with a mounting hole 19 having an inner peripheral surface 19 a and a bottom surface 19 b that is open at the end 17 a side, and a base end 18 a of the base 18 abutting on the end 11 a of the holder body 11. And a cylindrical mounting portion 20 coaxially protruding from the holder main body 11. The mounting portion 20 is inserted into the mounting hole 12 of the holder main body 11, and is locked to the holder main body 11 by a key 13. Are fixed to the holder main body 11 by bolts 14 which are screwed into the top portion and abut against a chamfered portion 20 a formed on the mounting portion 20, thereby being arranged on the central axis line a.
[0043]
The distal end member 21 has a first inner peripheral surface 22a having a relatively large diameter from the distal end 21a side coaxially along the center axis thereof, and a second inner peripheral surface having a diameter smaller than the first inner peripheral surface 22a and serving as a collet holding portion. 22b, a third inner peripheral surface 22c smaller in diameter than the second inner peripheral surface 22b, and a fourth inner peripheral surface 22d slightly smaller in diameter than the third inner peripheral surface 22c and serving as a holding portion of the center shaft member 36 are sequentially stepped 22e, 22f, A central shaft member insertion hole 22 continuously formed through 22g is formed. On the other hand, a first outer peripheral surface 23a having substantially the same diameter as the outer periphery of the intermediate holder 17 from the front end 21a side, and a second outer peripheral surface 23b fitted into the inner peripheral surface 19a of the mounting hole 19 formed in the base 18 of the intermediate holder 16; The third outer peripheral surface 23c having a diameter smaller than that of the second outer peripheral surface 23b is connected to the outer peripheral portion 23 which is continuously formed via a step 23d abutting on the front end 17a of the intermediate holder 17 and a step 23e serving as a spring receiving portion. It has a substantially cylindrical shape.
[0044]
The tip member 21 thus formed is in a state in which the second outer peripheral surface 23b is fitted into the mounting hole 19 formed in the base of the intermediate holder 17, and the step portion 23d is in contact with the tip 17a of the intermediate holder 17. The top is coaxially fixed to the intermediate holder 17 by a bolt 24 screwed into the intermediate holder 17 and having a top portion abutting against a concave portion 23f formed in the second outer peripheral surface 23b.
[0045]
As shown in FIGS. 1 to 3, the collet 25 includes a base 26 having an outer periphery 26 a fitted on the second inner peripheral surface 22 b of the tip member 21, and a relatively thin cylinder extending concentrically from the base 26. A portion 27 and a sheet holding portion 28 formed at the tip of the cylindrical portion 27 are integrally formed, and a substantially cylindrical shape in which a center shaft member insertion hole 29 is formed so as to penetrate along the center axis of the collet 25. In addition, a small diameter portion 29a serving as a central shaft member holding portion for slidably holding the central shaft member 36 with a slightly smaller diameter is formed at a portion corresponding to the base 26 of the central shaft member insertion hole 29.
[0046]
The sheet holding portion 28 formed at the front end of the collet 25 has a substantially cylindrical shape whose outer periphery is enlarged at the front end of the cylindrical portion 27 as shown in FIG. The outer peripheral surface 31 is formed in a conical tapered surface shape which is reduced in diameter, and has an outer diameter that fits substantially into the inner peripheral surface 6 of the valve seat 5, and the inner peripheral surface 31 that is continuous with the central shaft member tank through hole 29 is on the distal end side. It is formed in the shape of a conical taper whose diameter increases as it moves. The front end surface 32 of the sheet holding portion 28 is flat and has a chamfer 32a along its periphery. Further, the collet 25 is formed with a plurality of slits 33 at equal intervals in the circumferential direction from the distal end surface 32 of the sheet holding portion 28 to a region near the base 26 of the cylindrical portion 27, and in this embodiment, six slits 33 are formed to hold the sheet. The part 28 is divided into six pieces at equal intervals in the circumferential direction.
[0047]
The collet 25 formed in this manner fits the outer peripheral surface 26a of the base 26 into the second inner peripheral surface 22b in a state where the sheet holding portion 28 protrudes from the distal end 21a of the distal end member 21, and screw the distal end member 21. In combination, the top portion is coaxially fixed to the distal end member 21 by a bolt 35 abutting on a concave portion 26f formed in the outer peripheral surface 26a of the base portion 26.
[0048]
The central shaft member 36 penetrates through the central shaft member insertion holes 22 and 29 of the tip member 21 and the collet 25, and is slidably fitted and supported on the fourth inner peripheral surface 22d of the tip member 21 and the small diameter portion 29a of the collet 25. And a tip portion 38 formed integrally with the tip of the shaft portion 37. The distal end portion 38 has a substantially umbrella shape having an outer peripheral surface 39 and a flat top end surface 40 which are enlarged in diameter toward the distal end side, and the outer peripheral surface 39 of the distal end portion 38 has an axis centered on the central axis of the central shaft member 36. It is formed in a spherical shape. On the other hand, a screw portion 41 is formed at the base end of the shaft portion 37, and a spring receiver 42 is screwed to the screw portion 41.
[0049]
The spring receiver 42 is formed on a cylindrical mounting portion 43 that is screwed and mounted on the screw portion 41, a spring support portion 44, and a spring support portion 44 whose diameter is increased in a ring shape from the base end of the mounting portion 43. And a stopper mounting portion 45 for supporting a cylindrical stopper 46.
[0050]
Further, a spring 48 as an urging means is elastically mounted in the mounting hole 19 of the intermediate holder 17 between the step 23 e of the tip member 21 and the spring support 44 of the spring receiver 42. The shaft member 36 is urged toward the holder main body 11 where the stopper 46 contacts the bottom surface 19 b of the mounting hole 19.
[0051]
The center shaft member 36 is pulled toward the holder main body 11 by the bias of the spring 48, and the spherical outer peripheral surface 39 of the distal end portion 38 is formed into a tapered surface of the sheet holding portion 28 of the collet 25. The cylindrical portion 27 divided by the slit 33 is elastically deformed by pressing and sliding in a ring shape over the entire circumference of the inner peripheral surface 31 so that the sheet holding portion 28 is evenly spread and the outer peripheral surface 30 is expanded. (Point B in FIG. 2 indicates a contact portion between the outer peripheral surface 39 and the inner peripheral surface 31). The cylindrical portion 27 divided by the slit 33 is elastically deformed by pressing and sliding in a ring shape over the entire periphery of the inner peripheral surface 31 formed in the tapered surface shape of the sheet holding portion 28 of the collet 25, thereby holding the sheet. By evenly expanding the portion 28, the center is centered on the central axis of the sheet holding portion 28. That is, the outer peripheral surface 39 of the leading end portion 38 and the inner peripheral surface 31 of the sheet holding portion 28 form a centripetal mechanism.
[0052]
When the stopper 46 contacts the bottom surface 19b of the mounting hole 19, the movement of the central shaft member 36 in the direction toward the holder body 11 is restricted and the expansion of the outer peripheral surface 30 is restricted. Therefore, the amount of diameter expansion of the outer peripheral surface 30 can be set by setting the length of the stopper 46 in advance, and the outer diameter of the outer peripheral surface 30 of the seat holding portion 28 can be set to the inner peripheral surface 6 of various valve seats 5. It can be adjusted according to the inner diameter of.
[0053]
On the other hand, when the diameter of the sheet holding portion 28 of the collet 25 is reduced by an external force, the diameter of the inner peripheral surface 31 formed in a tapered surface is reduced, so that the inner peripheral surface 31 becomes the outer periphery of the distal end portion 38 formed on the central shaft member 36. The distal end portion 38 is pressed against the surface 39 and is pushed toward the distal end side indicated by the arrow F against the urging force of the spring 48, and the outer peripheral surface 30 of the sheet holding portion 28 is reduced in diameter according to the external force.
[0054]
Here, if the intersection angle α between the central axis of the collet 25 and the central shaft member 36 and the inner peripheral surface 31 of the collet 25 is too small, the distal end is pressed by the inner peripheral surface 31 against the outer peripheral surface 39 of the distal end portion 38. The central shaft member 36 that moves to the right cannot obtain a smooth sliding movement, which affects the diameter reduction of the sheet holding portion 28 of the collet 25. On the other hand, if the intersection angle α is too large, When the diameter of the sheet holding portion 28 of the collet 25 is expanded by the outer peripheral surface 39 of the collet 25, there is a concern that the collet 25 may be misaligned with respect to the central axis of the central shaft member 36. Focusing on this, as a result of various experiments, as a result of reducing the diameter of the inner peripheral surface 31 of the collet 25, the distal end portion 38 of the central shaft member 36 is smoothly pushed out toward the distal end side, and the centering function is sufficiently ensured and the center misalignment is sufficiently reduced. It is preferable that the intersection angle α for suppressing and ensuring the diameter expansion of the sheet holding portion 28 by pressing the outer peripheral surface 39 of the distal end portion 38 of the center shaft member 36 be set to, for example, 25 ° ≦ α ≦ 45 °. Was confirmed.
[0055]
The press-fit holder 10 of the valve seat press-fitting device configured as described above has a holder main body 11, an intermediate holder 17 and a tip member 21 which are coaxially united and arranged along a central axis a thereof. A cylindrical base 26 is fitted to the fourth inner peripheral surface 22d of the center shaft member insertion hole 22 formed along the center axis of the member 21, and a collet 25 is provided. The shaft portion of the central shaft member 36 is formed by the small-diameter portion 29a formed at a portion corresponding to the base portion 26 of the central shaft member insertion hole 29 formed and the second inner peripheral surface 22b of the central shaft member insertion hole 22 of the tip member 21. 37 are supported so as to be able to reciprocate along the central axis, and the outer peripheral surface 39 formed into a spherical shape at the distal end portion 38 of the central shaft member 36 by the bias of a spring 48 is formed into a tapered surface shape of the collet 25. Sheet holding portion 28 of the collet 25 is held on the central axis a of the central axis member 36 is centripetal by abutting the ring among the entire circumference of the peripheral surface 31.
[0056]
Next, the operation of press-fitting the valve seat by the valve seat press-fitting device thus configured will be described.
[0057]
The press-fit holder 10 of the valve press-fitting device is moved to the parts transfer section in which the valve seat 5 is accommodated, and the holder main body 11 is moved along the central axis a by the hydraulic cylinder toward the valve seat 5 arranged in the parts transfer section. Let go forward. The distal end surface 32 of the sheet holding portion 28 of the collet 25 projecting from the distal end 21a of the distal end member 21 with the advancement of the holder main body 11 abuts on the valve seat 5, and the press-fit holder 10 is further advanced, so that the valve seat 5 The seat holding portion 28 is inserted into the valve seat 5 by being guided and guided by the chamfer 6a formed on the inner peripheral surface 6 and the chamfer 32a of the distal end surface 32 of the collet 25, and fitted into the inner peripheral surface 6 to fit the valve seat. Hold 5. The diameter of the valve seat 5 held by the seat holding portion 28 is reduced by the inner peripheral surface 6 in accordance with the insertion of the seat holding portion 28 into the valve seat 5. Is pressed against the outer peripheral surface 39 of the distal end portion 38 of the central shaft member 36, and the distal end portion 38 is pushed to the distal end side against the urging force of the spring 48. As a result, the diameter of the outer peripheral surface 30 of the seat holding portion 28 is reduced, and the seat holding portion 28 can be easily inserted into the valve seat 5. After the seat holding portion 28 is inserted until the valve seat 5 contacts the front end 21a of the front end member 21, the holder 10 is retracted by the hydraulic cylinder, and the valve seat 5 is taken out from the parts transfer portion.
[0058]
When the holder 10 is taken out of the part transfer portion, the center shaft member 36 is pulled in the holder body 11 side by the urging force of the spring 48, and the spherical outer peripheral surface 39 of the distal end portion 38 is moved to the collet 25. The outer peripheral surface 30 of the inner peripheral surface of the valve seat 5 is uniformly expanded by pressing the seat retaining portion 28 in a ring shape over the entire circumference of the inner peripheral surface 31 formed in the tapered surface shape of the seat retaining portion 28. The valve seat 5 is held by the seat holding portion 28 in a state in which the valve seat 5 is in close contact with the tube 6 and the misalignment is avoided.
[0059]
Subsequently, the press-fit holder 10 holding the valve seat 5 by the seat holding unit 28 was moved to the working position, and the center axis of the valve seat fitting hole 2 of the cylinder head 1 was aligned with the center axis a of the press-fit holder 10. In this state, the press-fit holder 10 is advanced by the hydraulic cylinder.
[0060]
As the press-fit holder 10 advances, the valve seat 5 held by the seat holding portion 28 of the collet 25 is pressed into the valve seat fitting hole 2 in a state where the valve seat 5 is in contact with the tip 21a of the tip member 21. When the valve seat 5 is press-fitted to the bottom 2a of the valve seat fitting hole 2, the press-fit holder 10 is retracted and returned. At this time, the outer peripheral surface 39 formed on the distal end portion 38 by the urging force of the spring 48 rather than the press-fit holding force between the valve seat fitting hole 2 and the valve seat 5 causes the seat holding portion 28 of the collet 25 to expand in diameter. Therefore, since the holding force for holding the valve seat 5 is extremely small, the valve seat 5 is retracted and returned while leaving the valve seat 5 on the valve seat fitting hole 2 side.
[0061]
As described above, according to the present embodiment, the press-fit holder 10 is configured such that the holder main body 11, the intermediate holder 17 and the distal end member 21 are coaxially and integrally connected along the central axis a thereof, A collet 25 is provided by fitting into a center shaft member insertion hole 22 formed along the center axis of the base 21, and a base 26 of a center shaft member insertion hole 29 formed along the center axis of the collet 25. The shaft 37 of the central shaft member 36 is reciprocally supported by the small-diameter portion 29a formed at a portion corresponding to the above and the fourth inner peripheral surface 22d of the central shaft member insertion hole 22 of the distal end member 21. The outer peripheral surface 39 formed in a spherical shape on the distal end portion 38 of the center shaft member 36 by the urging is brought into contact with the entire peripheral surface of the inner peripheral surface 31 formed in a tapered surface shape of the collet 25 in a ring shape. this The valve seat 5 is held in close contact with the outer peripheral surface 30 of the seat holding portion 28, the valve seat 5 is held on the center axis a, and the cylinder head 1 The valve seat 5 can be press-fitted into the valve seat fitting hole 2 in a state in which the occurrence of misalignment with respect to the formed valve seat fitting hole 2 is extremely suppressed, and a smooth press-fitting operation of the valve seat 5 can be performed. Resulting in increased productivity.
[0062]
(2nd Embodiment)
Next, a second embodiment of the valve seat press-fitting device of the present invention will be described with reference to FIG.
[0063]
FIG. 4 is a cross-sectional view showing an outline of the valve seat press-fitting device. The same reference numerals are given to the portions corresponding to FIGS. 1 to 3 and the detailed description of the portions is omitted, and different portions are mainly described. Will be described.
[0064]
The distal end member 21 in the present embodiment is coaxially arranged along the central axis and has a first inner peripheral surface 22a having a relatively large diameter from the distal end 21a side and a collet holding portion having a smaller diameter than the first inner peripheral surface 22a. The second inner peripheral surface 22b, and a central shaft member having a smaller diameter than the second inner peripheral surface 22b and a third inner peripheral surface 22c having a slightly larger diameter than the shaft portion 37 of the central shaft member 36 are sequentially formed through a stepped portion. A hole 22 is formed, and an elastic member mounting groove 22h is formed in a ring shape on the third inner peripheral surface 22c.
[0065]
On the other hand, the collet 25 includes a base 26 fitted to the second inner peripheral surface 22b of the tip member 21, a cylindrical portion 27 extending from the base 26, and a sheet holding portion 28 formed at the distal end of the cylindrical portion 27. A central shaft member insertion hole 29 having a diameter slightly larger than the shaft portion 37 of the central shaft member 36 is formed and formed along the central axis, and is formed in a portion corresponding to the base 26 of the central shaft member insertion hole 22. The elastic member mounting groove 29h is formed in a ring shape.
[0066]
Further, a guide pin 51 that protrudes coaxially with the central axis of the central shaft member 36 is provided at the distal end of the distal end portion 38 of the central shaft member 36. The guide pin 51 has a columnar shape having a diameter that can be fitted into the guide hole 4 of the valve guide 3, and has a chamfer 51 a on the outer periphery of the distal end for guiding when the guide pin is inserted into the guide hole 4.
[0067]
The central shaft member 36 formed in this way has a shaft portion 37 that penetrates through the central shaft member insertion hole 22 of the distal member 21 and the central shaft member insertion hole 29 of the collet 25 with a clearance C1, and the distal member 21 and the collet The O-rings 52, 53, which are annular elastic members mounted in the elastic member mounting grooves 22h, 29h formed in the 25 central shaft member insertion holes 22, 29, are attached so as to be coaxial with the central axis a. It is floatingly supported in a biased state, and is further urged toward the holder main body 11 by a spring 48 elastically mounted between a spring receiver 42 provided at the base end and the intermediate holder 17.
[0068]
The outer peripheral surface 39 formed in a spherical shape on the distal end portion 38 of the central shaft member 36 is biased by the spring 48 so that the outer peripheral surface 39 is formed into a ring shape over the entire circumference of the tapered inner peripheral surface 31 of the collet 25. The contact is centered by the contact, and the sheet holding portion 28 of the collet 25 is held by being biased on the central axis a with the misalignment suppressed.
[0069]
The press-fitting operation of the valve seat by the valve seat press-fitting device is performed by first moving the press-fit holder 10 of the valve press-fitting device to the part transfer section in which the valve seat 5 is accommodated, as in the first embodiment. When the holder main body 11 is advanced along the central axis a toward the valve seat 5 disposed in the portion, the seat holding portion 28 is fitted to the inner peripheral surface 6 of the valve seat 5 to hold the valve seat 5, In addition, the holder 10 is retracted, and the valve seat 5 is taken out from the parts transfer section.
[0070]
Subsequently, the press-fit holder 10 holding the valve seat 5 by the seat holding unit 28 is moved to the working position, and the center axis of the valve seat fitting hole 2 of the cylinder head 1 is aligned with the center axis of the press-fit holder 10. Then, the press-fit holder 10 is advanced by the hydraulic cylinder.
[0071]
As the holder body 11 advances, the tip of a guide pin 51 protruding from the tip 38 of the central shaft member 36 is inserted into the guide hole 4 of the valve guide 3 on the cylinder head 1 side. The valve seat 5 held by the seat holding portion 28 of the collet 25 maintained coaxially with the central shaft member 36 by the distal end portion 38 of the central shaft member 36 while being guided and guided by the valve guide 3 and the valve seat 3. Press-fit into 2.
[0072]
When the valve seat 5 is press-fitted, the center shaft member 36 is floated by O-rings 52 and 53 mounted in the elastic member mounting grooves 22h and 29h formed in the center member insertion holes 22 and 29 of the tip member 21 and the collet 25. Since the seat holding portion 28 of the collet 25 is held coaxially with the center shaft member 36 by being supported, there is a slight difference between the center axis a of the holder body 11 and the center axis of the valve seat fitting hole 2. When there is a misalignment, the misalignment between the valve seat 5 and the valve seat 5 held by the seat holding portion 28 of the collet 25 with respect to the valve seat fitting hole 2 is adjusted by the elastic deformation of the O-rings 52 and 53, and the valve seat is fitted. The valve seat 5 can be smoothly pressed into the valve seat fitting hole 2 in a state in which the occurrence of misalignment with respect to the mating hole 2 is extremely suppressed. In addition to the embodiment, a more favorable press-fitting operation of the valve seat 5 is obtained, and the productivity is improved, and the center axis a of the press-in holder 10 and the central axis of the valve seat fitting hole 2 are used for the valve seat press-fitting. The tolerance of the misalignment is increased, and the required accuracy of the valve seat and the press-fitting device is relaxed.
[0073]
(Third embodiment)
Next, a third embodiment of the valve seat press-fitting device of the present invention will be described with reference to FIG.
[0074]
FIG. 5 is a cross-sectional view showing the outline of the valve seat press-fitting device. The parts corresponding to those in FIGS. 1 to 3 are denoted by the same reference numerals, and detailed description of the parts is omitted. Will be described.
[0075]
The intermediate holder 17 in the present embodiment can be inserted with a clearance C2 between the cylindrical mounting portion 20 and the inner peripheral surface 12a of the mounting hole 12 of the holder body 11, and the mounting portion 20 A ring-shaped elastic member mounting groove 20d is formed in the vicinity of the distal end along the outer peripheral surface 20c, and elastic member mounting grooves 20e and 20f are formed in the vicinity of the base 18. A mounting hole 20g is penetrated from the tip of the mounting portion 20 and penetrates the mounting hole 20g with a clearance C3, and both ends are swingably supported by a support shaft 55 fixed to the holder body 11. I have.
[0076]
The O-rings 56, 57, and 58, which are annular elastic members that are mounted in the respective elastic member mounting grooves 20d, 20e, and 20f and pressed against the inner peripheral surface 12a of the mounting hole 12, make the center axis of the mounting portion 20 coincide with the center axis a. The intermediate holder 17 is floatingly supported while being urged to be coaxial. In particular, the two O-rings 57 and 58 are arranged on the base portion 18 to secure rigidity and prevent the intermediate holder 17 from being biased to one side due to the weight of the press-fit holder 10 or the like.
[0077]
On the other hand, a guide pin 51 that protrudes coaxially with the axis of the central shaft member 36 is provided at the distal end of the distal end portion 38 of the central shaft member 36 as in the second embodiment. The guide pin 51 has a columnar shape having a diameter that can be fitted into the guide hole 4 of the valve guide 3, and has a chamfer 51 a on the outer periphery of the distal end for guiding when the guide pin is inserted into the guide hole 4.
[0078]
The press-fitting holder 10 of the valve seat press-fitting device configured as described above includes the O-rings 56 and 57 in which the intermediate holder 17 is elastically mounted between the base 18 and the inner peripheral surface 12 a of the mounting hole 12 of the holder main body 11. , 58 in a state of being urged to be coaxial with the center axis a in a floating state, and the intermediate holder 17 is provided with the tip member 21, the collet 25, the center shaft member 36, and the spring receiver as in the first embodiment. The valve seat holding portion 15 provided with a spring 42, a spring 48, and the like is provided, and the seat holding portion 28 of the collet 25 is held on the center axis a with the center deviation suppressed.
[0079]
The press-fitting operation of the valve seat by the valve seat press-fitting device is performed by first moving the press-fit holder 10 of the valve press-fitting device to the parts transfer section in which the valve seat 5 is accommodated, as in the first embodiment. When the holder main body 11 is advanced along the central axis a toward the valve seat 5 disposed in the valve seat 5, the seat holding portion 28 is inserted into the valve seat 5 and fitted to the inner peripheral surface 6 thereof so as to fit into the valve seat 5. , And the valve seat 5 is taken out from the parts transfer part by retreating the press-in holder 10.
[0080]
Subsequently, the press-fit holder 10 holding the valve seat 5 by the seat holding unit 28 was moved to the working position, and the center axis a of the press-fit holder 10 was aligned with the center axis of the valve seat fitting hole 2 of the cylinder head 1. In this state, the press-fit holder 10 is advanced by the hydraulic cylinder.
[0081]
As the holder body 11 advances, the tip of a guide pin 51 protruding from the tip 38 of the central shaft member 36 is inserted into the guide hole 4 of the valve guide 3 on the cylinder head 1 side. The valve seat 5 held by the seat holding portion 28 of the collet 25 maintained coaxially with the central shaft member 36 by the distal end portion 38 of the central shaft member 36 while being guided and guided by the valve guide 3 and the valve seat 3. Press-fit into 2.
[0082]
When the valve seat 5 is press-fitted, the intermediate holder 17 is formed by O-rings 56, 57, and 58, which are annular elastic members mounted in the elastic member mounting grooves 20d, 20e, and 20f and pressed against the inner peripheral surface 12a of the mounting hole 12. Is floatingly supported, and if there is a slight misalignment between the center axis a of the holder body 11 and the center axis of the valve seat fitting hole 2, the O-rings 56, 57, 58 are elastically deformed. The misalignment between the valve seat fitting hole 2 and the valve seat 5 held by the seat holding portion 28 of the collet 25 is adjusted, and the occurrence of misalignment with respect to the valve seat fitting hole 2 is extremely suppressed. 5 can be smoothly press-fitted into the valve seat fitting hole 2, and in addition to the above-described first embodiment, a better press-fitting operation of the valve seat 5 can be obtained, thereby improving productivity. It is brought, and the required accuracy of the increased tolerance of misalignment of the center axis a and the center axis of the valve seat fitting hole 2 of the press-fit holder 10 Upon valve seat press-fitted in the valve seat press-fitting device is relaxed.
[0083]
The present invention is not limited to the above embodiments, and can be variously modified without departing from the spirit of the present invention. For example, in each of the above embodiments, the stopper 46 is attached to the center shaft member 36, but it may be provided on the bottom surface 19b of the mounting hole 19 formed in the intermediate holder 17.
[0084]
【The invention's effect】
According to the valve seat press-fitting device of the present invention, the valve seat is held by the press-fit holder, and the press-fit holder is advanced to the valve seat fitting hole formed in the cylinder head to press-fit the valve seat into the valve seat fitting hole. In the valve seat press-fitting device, the diameter of the seat holding portion of the collet is expanded by the central shaft member, and the valve seat is fitted and held on the outer periphery of the collet, thereby avoiding or extremely generating a misalignment with the seat holding portion. The valve seat can be held in a state in which the valve seat is suppressed, and the valve seat can be pressed into the valve seat fitting hole of the cylinder head in a state in which the misalignment between the valve seat and the valve seat fitting hole is suppressed. As a result, smooth press-fitting of the valve seat can be obtained, and a significant improvement in productivity can be expected.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an outline of a first embodiment of a valve seat press-fitting device according to the present invention.
FIG. 2 is an enlarged view of a portion A in FIG.
FIG. 3 is a sectional view taken along line II of FIG. 1;
FIG. 4 is a sectional view showing an outline of a second embodiment of the valve seat press-fitting device according to the present invention.
FIG. 5 is a sectional view showing an outline of a third embodiment of the valve seat press-fitting device according to the present invention.
FIG. 6 is a sectional view showing an outline of a conventional valve seat press-fitting device.
FIG. 7 is a sectional view showing an outline of a conventional valve seat press-fitting device.
8 is a sectional view taken along line II-II of FIG.
[Explanation of symbols]
1 cylinder head
2 Valve seat fitting hole
3 Valve guide
5 Valve seat
10 Press-in holder
11 Holder body
11a Tip
12 Mounting holes
15 Valve seat holder
16 Tip holder
17 Intermediate holder
17a Tip
18 Base
18a proximal end
19 Mounting hole
19a Inner circumference
19b bottom
20 Mounting part
21 Tip member
21a Tip
22 Center shaft insertion hole
25 collets
26 base
27 cylindrical part
28 Sheet holder
29 Center shaft insertion hole
30 Outer surface
31 Inner circumference
32 Tip surface
33 slit
36 Central shaft member
37 Shaft
38 Tip
39 Outer surface
42 Spring holder
46 Stopper
48 spring (biasing means)
51 Guide pin
52, 53, 56, 57, 58 O-ring (elastic member)

Claims (10)

A valve seat press-fitting device that holds a valve seat in a press-fit holder, advances the press-fit holder to a valve seat fitting hole formed in a cylinder head, and press-fits the valve seat into the valve seat fitting hole.
The press-fit holder is
A holder body that moves forward along a valve seat fitting hole formed in the cylinder head along a central axis of the press-fit holder;
A tip holder supported by the tip of the holder body,
The sheet holder is supported by the tip holder and protrudes from the tip of the tip holder to form a sheet holding portion, and is formed in a substantially cylindrical shape having a center shaft member insertion hole formed therein. A collet having a plurality of slits for dividing into a plurality,
A central shaft member that is disposed so as to be axially movable through the central shaft member insertion hole,
Urging means for urging the center shaft member toward the holder body,
The diameter of the seat holding portion is expanded by urging the center shaft member toward the holder body by the urging means, and the valve seat is fitted and held on the outer periphery of the seat holding portion by the diameter expansion. Valve seat press-fitting device. 2. The valve seat press-fitting device according to claim 1, further comprising a centering mechanism for centering the seat holding portion on the center axis of the center shaft member in response to the biasing of the center shaft member toward the holder body. . The collet has a substantially conical tapered inner peripheral surface centered on the central axis of the collet which is continuous with the distal end of the central shaft member insertion hole and which is expanded toward the distal end side in the seat holding portion. Prepare,
A distal end portion having a substantially conical tapered outer peripheral surface centered on the central axis of the central shaft member, which is enlarged in diameter as it moves toward the distal end to the distal end of the central shaft member and abuts against the inner peripheral surface of the collet. The valve seat press-fitting device according to claim 1 or 2, further comprising: The valve seat press-fitting device according to claim 3, wherein an outer peripheral surface of the tip portion has a substantially spherical shape having a center axis of the center shaft member as an axis. The valve seat press-fitting device according to claim 3 or 4, wherein an intersection angle between a center axis of the collet and the inner peripheral surface is in a range of 25 ° to 45 °. The valve seat press-fitting device according to any one of claims 1 to 5, wherein the center shaft member is held by the tip holder so as to be movable coaxially with a center axis of the press-fit holder. The center shaft member is inserted with a clearance into a center shaft member insertion hole formed in the tip holder, and is floated by an annular elastic member interposed between the center shaft member insertion hole and the center shaft member. The valve seat press-fitting device according to any one of claims 1 to 5, which is supported. In the tip holder, a column-shaped mounting portion extending to the base end side of the tip holder is inserted with a clearance into a mounting hole drilled in the holder body, and between the mounting member and the mounting hole. The valve seat press-fitting device according to any one of claims 1 to 5, wherein the valve seat is press-fitted by an interposed annular elastic member. 9. The guide pin according to claim 7, further comprising a guide pin protruding coaxially with the center axis of the center shaft member and capable of being fitted into a valve guide provided on a cylinder head. Valve seat press-fitting device. The valve seat according to any one of claims 1 to 9, wherein a stopper for restricting movement of the center shaft member in the holder body side direction is provided between the center shaft member and the tip holder. Press-in device.

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