JP2005098442A - Method of manufacturing pole retainer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce manufacturing cost for a pole retainer by simplifying the construction of a forming die. <P>SOLUTION: A female mold 100 is prepared which has first cavities 100B, 100C for molding an outside face 80B and a lower face 80C of the pole retainer 80 and first core portions 100a, 100b protruded into the first cavities 100B, 100C for molding a pole storage hole 80a and a spring storage hole 80b. A male mold 101 is prepared which has a second cavity 101A for molding an upper face 80A of the pole retainer 80 and a second core portion protruded into the second cavity 101A and adapted to be integrated in engagement with the first core portions 100a, 100b during mold clamping for molding the spring storage hole 80b. The pole retainer 80 is formed by introducing molten metal or molten resin into the cavities in the state of mold clamping the female mold 100 and the male mold 101 for injection molding. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hydraulic tensioner for applying an appropriate tension force to a chain or a belt, and more particularly, to engage with rack teeth on the outer periphery of a piston in order to prevent the piston from contracting when the hydraulic pressure is lowered. The present invention relates to a pole retainer for accommodating a pole member provided in the housing.

  The hydraulic tensioner is generally mainly composed of a housing, a piston slidably inserted into a piston hole formed in the housing and biased in a protruding direction by a piston spring, and a fluid chamber defined by the piston hole and the piston. It is configured. During the operation of the tensioner, the pressing force acting on the piston tip from the chain or belt is balanced with the elastic repulsion force due to the piston spring and the drag force due to the fluid pressure in the chamber.

  By the way, in a hydraulic tensioner applied to a timing system for automobiles in particular, a pressing force is applied from the chain to the piston tip in a situation where sufficient hydraulic pressure does not act in the chamber, such as when the engine is started. In this case, the piston is easily pushed into the housing and the piston is retracted. As a result, noise and vibration may occur.

  Therefore, in order to prevent such piston degeneration, various hydraulic tensioners having a ratchet mechanism as shown in, for example, Japanese Patent Laid-Open Nos. 2000-136859 and 2001-304360 have been proposed. Yes.

  Japanese Patent Laid-Open No. 2000-136859 discloses a rack that is movably supported in a vertical hole formed in a housing, and is slidably accommodated in a lateral cavity formed in the housing. It is composed of a mating ratchet and a spring which is accommodated in the cavity and biases the ratchet in a direction to engage with the rack.

  However, in this case, a rack is provided separately from the plunger, and the number of parts is large. In addition, in the case of a chain having a relatively long inter-core distance, there is a request to increase the backlash of the ratchet mechanism to some extent. However, in the above publication, the backlash of the ratchet mechanism is reduced between the rack and the ratchet. There is a disadvantage that it cannot be more than rush.

  In the one disclosed in Japanese Patent Laid-Open No. 2001-304360, a rack groove formed on the outer periphery of the piston and a lateral hole extending in a direction intersecting with the axis of the piston in the housing are slidably accommodated through a predetermined play with the inner wall surface. The claw member that engages with the rack groove, and a spring that is accommodated in the lateral hole and biases the claw member in a direction that engages with the rack groove.

  In this case, it is not possible to make the backlash of the ratchet mechanism more than the backlash between the groove and the claw member by providing a predetermined play between the claw member and the inner wall surface of the lateral hole. is there. However, in this case, if the play is too large, the claw member may chatter inside the side hole, so the amount of play cannot be increased so much that the backlash of the ratchet mechanism is sufficiently large. It is difficult to do.

  Accordingly, the present applicant has proposed a hydraulic tensioner having a ratchet mechanism as disclosed in JP-A-2003-240071. This ratchet mechanism is provided slidably along an inclined slide surface formed inside a support block (pole retainer), and engages with a rack tooth on the outer periphery of a plunger (piston). And a wedge-shaped slider (pole member) and a spring (pole spring) for biasing the slider in the direction of engagement with the rack teeth.

  In this case, since the pole member moves along the inclined slide surface of the pole retainer, it is possible to increase the backlash amount of the entire ratchet mechanism while suppressing chattering of the pole member.

However, in this case, a core pin or core mold for forming the pole spring accommodation hole is required in addition to the upper mold and the lower mold for forming the pole retainer main body as the mold for forming the pole retainer. For this reason, the configuration of the entire molding die is complicated, and the molding process is also complicated.
JP 2000-136859 A JP 2001-304360 A JP 2003-240071 A

  The problem to be solved by the present invention is to simplify the structure of a molding die for molding a pole retainer of a hydraulic tensioner.

  The main feature of the present invention is that the pole retainer is formed from two upper and lower molds.

According to the first aspect of the present invention, in the hydraulic tensioner, the pole member having a tooth portion engaged with the rack teeth on the outer periphery of the piston on the lower surface is slid so as to allow movement of the piston in the protruding direction and restrict movement in the backward direction. Manufacturing of a pole retainer having a pole receiving hole for receiving freely and a spring receiving hole for receiving a pole spring that communicates with the pole receiving hole and biases the pole member in the direction of engagement with the rack teeth Is the method. This manufacturing method includes the following steps. Ie
(i) a first core portion having a first cavity for molding the outer surface and the lower surface of the pole retainer and projecting into the first cavity for molding a pole housing hole and a spring housing hole; A step of preparing a lower mold having
(ii) It has a second cavity for molding the upper surface of the pole retainer, protrudes into the second cavity to mold the spring accommodating hole, and engages with the first core portion during mold clamping. A step of preparing an upper mold having a second core part to be integrated.
(iii) Injecting molten metal, powdered metal or molten resin into the first and second cavities with the lower mold and upper mold clamped, or performing the injection molding method, or lower mold and upper mold The process of forming a pole retainer by sintering using

  In the invention of claim 2, the first core portion has the first stepped portion, and the second stepped portion that can be engaged with the first stepped portion at the time of mold clamping is the second core. Part has.

  In the invention of claim 3, the second core portion extends inside the first core portion so that the first core portion forms the bottom of the spring accommodating hole, and at the time of mold clamping, A gap for introducing metal or resin is formed at the tip of the core portion.

  In the invention of claim 4, the second core portion is disposed at the end of the first core portion so that the second core portion forms the bottom of the spring accommodating hole, and at the time of mold clamping, A gap for introducing metal or resin is formed at the tip of the core portion.

  In the invention of claim 5, the injection molding method is a molten metal injection molding method which is performed by introducing a molten or semi-molten metal.

  In the invention of claim 6, the injection molding method is a metal powder injection molding method which is performed by introducing a metal having a plasticity by mixing and kneading a metal powder and a binder.

  In the invention of claim 7, the injection molding method is a molten resin injection molding method which is performed by introducing a molten resin.

  The pole retainer according to the invention of claim 8 is formed by the method of any one of claims 1 to 7.

  A hydraulic tensioner according to a ninth aspect of the invention includes the pole retainer according to the eighth aspect.

  The mold for forming a pole retainer according to the invention of claim 10 has a first cavity for forming the outer surface and the lower surface of the pole retainer, and the first mold for forming the pole accommodation hole and the spring accommodation hole. A lower mold having a first core portion projecting into the cavity of the first and a second cavity for molding the upper surface of the pole retainer, and projecting into the second cavity to mold the spring accommodating hole And an upper mold having a second core part that is engaged and integrated with the first core part during mold clamping.

  In the method for manufacturing a pole retainer according to the present invention, the first core portion is provided in the lower die, and the second core portion that is engaged and integrated with the first core portion at the time of clamping is provided in the upper die. Since the spring accommodating hole is formed by the first and second core portions, the pole retainer can be formed from the two upper and lower molding dies, thereby forming the molding dies. Can be simplified, and the cost can be reduced.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
1 is a longitudinal sectional view of a hydraulic tensioner according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view of a pole retainer, FIG. 3 is a sectional view taken along line III-III in FIG. 2, and FIG. 5 is a cross-sectional view taken along the line VV in FIG. 2, and FIG. 6 is a schematic vertical cross-sectional view of a mold for forming the pole retainer.

  As shown in FIG. 1, the hydraulic tensioner 1 includes a housing 2, a hollow piston 3 slidably inserted into a piston hole 2a formed in the housing 2, and a direction in which the piston 3 protrudes from the piston hole 2a. It is mainly composed of a piston spring 4 that urges the spring.

  In the housing 2, a fluid chamber 30 is formed from an inner space 3a formed in the piston 3 and an inner wall surface of the piston hole 2a. A check valve 5 is provided in the housing 2 at the bottom of the piston hole 2a. The check valve 5 is for preventing the flow of fluid in the opposite direction while allowing the flow of fluid into the chamber 30. The ball 50 and a ball seat against which the ball 50 abuts. 51 and a ball spring 52 that urges the ball 50 toward the ball seat 51. The housing 2 is provided with a flow path 6 for connecting the chamber 20 to an external pressurized fluid source (not shown).

  A relief valve 7 is provided on the piston head side in the internal space 3 a of the piston 3. The relief valve 7 is a member for releasing the pressure in the fluid chamber 20 when the pressure in the fluid chamber 30 is increased to a predetermined pressure or higher.

  Rack teeth 3 b are formed on part of the outer peripheral surface of the piston 3. On the other hand, a pole retainer hole 2b communicating with the piston hole 2a is formed in the housing 2, and a pole retainer 80 is disposed in the pole retainer hole 2b. In the pole accommodation hole 80a formed in the pole retainer 80, a wedge-shaped pole member 81 is accommodated slidably along the inclined surface of the pole accommodation hole 80a. The pole member 81 has a tooth portion 81a on the lower surface that engages with the rack teeth 3b of the piston 3 and is formed so as to allow movement of the piston 3 in the protruding direction and restrict movement in the backward direction. Further, the pole retainer 80 is formed with a spring accommodation hole 80b communicating with the pole accommodation hole 80a, and the tooth portion 81a of the pole member 81 engages with the rack tooth 3b of the piston 3 in the spring accommodation hole 80b. A pole spring 82 for energizing the pole member 81 in the direction is accommodated.

  The rack teeth 3b, the pole retainer 80, the pole member 81, and the pole spring 82 constitute a ratchet mechanism 8.

Here, the operation of the hydraulic tensioner will be briefly described.
When the chain is slackened or the chain tension is reduced during operation of the hydraulic tensioner, the piston 3 moves in a direction in which the piston 3 protrudes from the housing 2 due to the spring force of the piston spring 4. At this time, the rack teeth 3b of the piston 3 move while engaged with the teeth 81a of the pole member 81 or over the teeth 81a of the pole member 81.

  When the piston 3 moves in the protruding direction, the pressure in the fluid chamber 30 becomes negative, whereby the check valve 5 is opened, and engine oil is introduced from the flow path 6 through the check valve 5 into the fluid chamber 30. As a result, the resultant force of the spring force of the piston spring 4 and the hydraulic pressure in the fluid chamber 30 acts on the chain from the piston tip 3c via the tensioner arm, and the chain tension is maintained.

  On the other hand, when a pressing force is applied from the chain to the piston tip 3c under a situation where sufficient fluid pressure is not applied in the fluid chamber 30 such as when starting the engine, the rack teeth 3b on the outer periphery of the piston are The piston 3 moves backward together with the pole member 81 while maintaining the state of being engaged with the tooth portion 81 a of the member 81. At this time, the wedge-shaped pole member 81 exhibits a wedge effect between the pole accommodation hole 80a and the rack teeth 3b on the outer periphery of the piston, and the rear end surface of the pole member 81 abuts against the inner wall surface of the pole accommodation hole 80a. As a result, the movement of the pole member 81 is prevented, so that the piston 3 is reliably prevented from contracting.

Next, details of the pole retainer 80 are shown in FIGS.
The pole retainer 80 is a member having a substantially gate-like vertical cross section as shown in FIG. 2 and is formed by an injection molding method or sintering using a metal or a resin, as will be described later. As shown in FIGS. 3 and 4, the pole retainer 80 has an upper surface 80A having a semicircular cross section, a planar outer surface 80B extending downward, and a planar lower surface 80C. Further, the pole retainer 80 is formed with a vertical through hole 80c that opens to the upper surface 80A (see FIG. 5), and the outer surface of the pole spring 82 (FIG. 1) is located below the through hole 80c. A support portion 80d is provided for supporting from the outside.

Next, a molding die for injection molding the pole retainer 80 will be described with reference to FIG.
The mold for forming the pole retainer 80 includes a lower mold 100 disposed below and an upper mold 101 disposed on the upper mold and clamped to the lower mold 100. Note that the sprue (casting port), runner (runner), gate (pouring gate), release knockout pin, cooling pipe, and the like, which are usually required for injection molding, are omitted in FIG. 6 for convenience of illustration. Has been.

  As shown in FIG. 6, the lower mold 100 includes first cavities 100B and 100C and first core portions 100a and 100b protruding into the first cavities 100B and 100C. The upper die 101 has a second cavity 101A and a second core portion 101b that protrudes into the second cavity 101A and extends between the first core portions 100a and 100b of the lower die 100. doing. In addition, the English character in each reference code corresponds with the English character in the reference code of the corresponding part in the pole retainer of FIG.

  That is, the outer surface 80B of the pole retainer 80 is formed by the first cavity 100B, and the lower surface 80C of the pole retainer 80 is formed by the first cavity 100C. Similarly, the upper surface 80A of the pole retainer 80 is formed by the second cavity 101A. Further, the pole housing hole 80a of the pole retainer 80 is formed by the first core portion 100a, and the spring housing hole 80b of the pole retainer 80 is formed by the first core portion 100b. Similarly, the spring accommodating hole 80b of the pole retainer 80 is formed by the second core portion 101b. In addition, the through-hole 80c (FIG. 2) opened to the upper surface 80A of the pole retainer 80 is formed by the 2nd core part 101b after shaping | molding.

At the time of mold clamping shown in FIG. 6, the first core portion 100b of the lower die 100 and the second core portion 101b of the upper die 101 are engaged with each other and closely contacted with each other, and the two are integrated. . Preferably, as shown in the figure, the first core portion 100b has a stepped portion 100b _1, the second core portion 101b is has a stepped portion 101b _1, section 100b ₁ with each stage And 101b ₁ are engaged with each other. In addition, a gap 100d is formed between the tip of the second core portion 101b and the lower mold 100.

  As shown in FIG. 6, from the state in which the lower mold 100 and the upper mold 101 are brought into contact with each other and clamped, the melted or semi-molten metal or resin is first fed through a sprue, runner and gate (not shown). Are introduced into the cavities 100B and 100C, the second cavity 101A, and the gap 100d to perform injection molding. After molding, one mold is retracted and a knockout pin (not shown) is projected to separate the molded product from the mold. In this way, a series of injection molding steps is completed.

In this case, since the first and second core portions 100b and 101b are engaged and integrated when the lower mold 100 and the upper mold 101 are clamped, the spring accommodating hole 80b is formed. In a direction different from the separation direction of the lower mold 100 (arrow S ₀ direction in FIG. 6) or the separation direction of the upper mold 101 (arrow S ₁ direction in the figure) (direction orthogonal to the arrow S ₀ and S ₁ directions). The extending spring accommodating hole 80b can be formed by two molds.

  This eliminates the need for a third mold such as a core pin or core mold to mold the spring accommodating hole, simplifying the configuration of the pole retainer mold, and as a result, reducing the cost.

Further, in this case, the first and second core portions 100b and 101b are in close contact with each other through the stepped portions 100b ₁ and 101b ₁ during mold clamping, and are stepped on each core portion mating surface above the stepped portion. Each core portion mating surface below the attached portion is offset in the axial direction of the spring accommodating hole 80b. As a result, even when a burr is formed in the spring accommodation hole 80b after molding due to the molten metal or molten resin wrapping around the mating surfaces of the core portions 100b and 101b when the molten metal or resin is introduced, the spring accommodation hole 80b. It is possible to prevent the formation of burrs that are opposed to each other in the diametrical direction in the inside, and it is possible to prevent the inner diameter of the spring accommodating hole 80b from being locally reduced to adversely affect the incorporation and operation of the pole spring 82 (FIG. 1).

[Other Examples]
FIG. 7 shows a pole retainer according to another embodiment of the present invention, and FIG. 8 shows a mold for forming the pole retainer of FIG. In these drawings, the same reference numerals as those in the previous embodiment denote the same or corresponding parts.

  In the above-described embodiment, the example in which the second core portion 101b of the upper mold 101 is extended inside the first core portions 100a and 100b of the lower mold 100 has been described. However, the application of the present invention is not limited thereto. Instead, as shown in FIG. 8, the second core portion 101′b of the upper mold 101 ′ may be disposed at the end of the first core portion 100′a of the lower mold 100 ′. That is, in this case, there is no component corresponding to the first core portion 100b of the above embodiment.

As shown in FIG. 8, the first core portion 100'A stepped portion 100'A ₁ formed is a gap in engagement with the stepped portion 101'B ₁ of the second core portion 101'B They are in close contact, and both are integrated. The air gap 100'd at the tip of the second core portion 101'b is formed integrally with the first cavities 100'B and 100'C. Therefore, as shown in FIG. The support portion 80d 'is formed integrally with the inner wall surface of the spring accommodation hole 80'b. Further, the spring accommodation hole 80 ′ b is a vertical through-hole that opens in the upper surface 80 ′ A of the pole retainer 80.

Also in this case, as in the above embodiment, the first and second core portions 100'a and 101'b are engaged and integrated when the lower mold 100 'and the upper mold 101' are clamped. . Thus forming the spring accommodating hole 80'B, 'separating direction of the (arrow S ₀ in Fig. 8' lower die 100 direction) or the upper mold 101 'separating direction of the (arrow S ₁ in FIG.' direction) different from the direction (arrow S ₀ ', S _1' so the spring accommodating hole 80'b extending direction) perpendicular to the direction can be formed in two molds.

  This eliminates the need for a third mold such as a core pin or core mold to mold the spring accommodating hole, simplifying the configuration of the pole retainer mold, and as a result, reducing the cost.

Further, in this case, the first and second core portions 100'A during mold clamping, 101'B adhered closely through a stepped portion 100'a _1, 101'b _1, the upper stepped portion Each core portion mating surface and each core portion mating surface below the stepped portion are offset in the axial direction of the spring accommodating hole 80'b. Accordingly, when molten metal or molten resin is introduced, the molten metal or molten resin wraps around the mating surfaces of the core portions 100'a and 101'b, thereby forming a burr in the spring accommodating hole 80'b after molding. However, it is possible to prevent the formation of diametrically opposed burrs in the spring accommodating hole 80'b, and the inner diameter of the spring accommodating hole 80'b is locally reduced, so that the pole spring 82 (FIG. 1) It is possible to prevent adverse effects on the operation.

  In the embodiment and the other embodiments, a so-called molten metal injection molding method or a molten resin injection molding method in which a molten or semi-molten metal or resin is introduced from a state where the lower mold and the upper mold are clamped. However, the present invention may adopt a so-called metal powder injection molding method using metal powder mixed and kneaded with a binder such as resin and wax to give plasticity.

  In the present invention, the pole retainer 80 may be molded by sintering. In this case, the basic configuration of the molding die is the same as that shown in FIG. 6 or FIG. Description is omitted.

1 is a longitudinal sectional view of a hydraulic tensioner according to an embodiment of the present invention. It is a longitudinal cross-sectional view of the pole retainer which comprises a hydraulic tensioner (FIG. 1). It is the III-III sectional view taken on the line of FIG. It is the IV-IV sectional view taken on the line of FIG. It is the VV sectional view taken on the line of FIG. It is a longitudinal cross-sectional schematic diagram of the shaping | molding die of a pole retainer (FIG. 2). It is a longitudinal cross-sectional view of the pole retainer which comprises the hydraulic tensioner by other Example of this invention, Comprising: It is a figure corresponding to FIG. 2 of the said Example. It is a longitudinal cross-sectional schematic diagram of the shaping | molding die of a pole retainer (FIG. 7), Comprising: It is a figure corresponding to FIG. 6 of the said Example.

Explanation of symbols

1: Hydraulic tensioner

2: Housing 2a: Piston hole

3: Piston 3b: Rack tooth 30: Fluid chamber

4: Piston spring

8: Ratchet mechanism 80: Pole retainer 80A: Upper surface 80B: Outer side surface 80C: Lower surface 80a: Pole accommodation hole 80b: Spring accommodation hole 81: Pole member 81a: Tooth part 82: Pole spring

100: lower mold 100B: first cavity 100C: first cavity 100a: first core part 100b: first core part 100b ₁ : first stepped part

101: Upper mold 101A: Second cavity 101b: Second core portion 101b ₁ : Second stepped portion

Claims (10)

In a hydraulic tensioner, a pole for slidably receiving a pole member having a tooth portion on the lower surface that engages with a rack tooth on the outer periphery of the piston so as to allow movement in the protruding direction of the piston and restrict movement in the backward direction. A method of manufacturing a pole retainer having a housing hole and a spring housing hole for housing a pole spring that communicates with the pole housing hole and biases the pole member in a direction of engagement with the rack teeth. ,
A first cavity for forming an outer surface and a lower surface of the pole retainer, and a first core portion protruding into the first cavity for forming the pole accommodation hole and the spring accommodation hole; While preparing a lower mold with
A second cavity for molding the upper surface of the pole retainer; protrudes into the second cavity to mold the spring receiving hole; and engages with the first core during mold clamping. Prepare an upper mold having a second core part integrated with
The molten metal, powder metal or molten resin is introduced into the first and second cavities while the lower mold and the upper mold are clamped, and an injection molding method is performed, or the lower mold and the upper mold are The pole retainer was formed by sintering using
A method for manufacturing a pole retainer. In claim 1,
The first core portion has a first stepped portion, and the second core portion has a second stepped portion that can be engaged with the first stepped portion during mold clamping. Yes,
A method for manufacturing a pole retainer. In claim 2,
The second core portion extends inside the first core portion so that the first core portion forms the bottom of the spring accommodating hole, and the second core is clamped during mold clamping. A gap for introducing metal or resin is formed at the tip of the part,
A method for manufacturing a pole retainer. In claim 2,
The second core portion is disposed at an end of the first core portion so that the second core portion forms a bottom portion of the spring accommodating hole, and at the time of mold clamping, the second core A gap for introducing metal or resin is formed at the tip of the part,
A method for manufacturing a pole retainer. In claim 1,
The injection molding method is a molten metal injection molding method performed by introducing a molten or semi-molten metal.
A method for manufacturing a pole retainer. In claim 1,
The injection molding method is a metal powder injection molding method performed by introducing a metal having a plasticity by mixing and kneading a metal powder and a binder,
A method for manufacturing a pole retainer. In claim 1,
The injection molding method is a molten resin injection molding method performed by introducing a molten resin.
A method for manufacturing a pole retainer.   A pole retainer formed by the method according to claim 1.   A hydraulic tensioner comprising the pole retainer according to claim 8. In a hydraulic tensioner, a pole for slidably receiving a pole member having a tooth portion on the lower surface that engages with a rack tooth on the outer periphery of the piston so as to allow movement in the protruding direction of the piston and restrict movement in the backward direction. A gold for forming a pole retainer having a receiving hole and a spring receiving hole for receiving a pole spring that communicates with the pole receiving hole and urges the pole member in an engagement direction with the rack teeth. Type,
A first cavity for forming an outer surface and a lower surface of the pole retainer, and a first core portion protruding into the first cavity for forming the pole accommodation hole and the spring accommodation hole; A lower mold having,
A second cavity for molding the upper surface of the pole retainer; protrudes into the second cavity to mold the spring receiving hole; and engages with the first core during mold clamping. And an upper mold having a second core part integrated with each other,
Mold with.

Images