JP4484557B2 - Tensioner body for hydraulic tensioner - Google Patents

Description

  The present invention relates to a tensioner body for a hydraulic tensioner having a pole ratchet mechanism.

  The hydraulic tensioner is generally a tensioner body (housing), a piston that is slidably inserted into a hole formed in the tensioner body, and is biased in a protruding direction by a spring, and a fluid chamber defined within the hole of the tensioner body. And mainly consists of During operation of the tensioner, the pressing force acting on the tip of the piston from the chain or belt balances the elastic repulsive force due to the spring and the drag force due to the hydraulic pressure in the chamber.

  By the way, particularly in a hydraulic tensioner applied to an auxiliary drive system such as an automobile timing system or an oil pump, there is no sufficient hydraulic pressure in the chamber such as when the engine is started. In this case, when a pressing force is applied from the chain to the tip of the piston, the piston is easily pushed into the tensioner body and the piston is retracted. As a result, noise and vibration may be generated.

  Therefore, in order to prevent such piston degeneration, a hydraulic tensioner having a pole ratchet mechanism as shown in US Pat. No. 5,304,099 has been proposed.

  The ratchet mechanism includes a rack tooth formed on a sleeve disposed on the outer periphery of the piston, a pole having a pointed portion which is received in a pole hole orthogonal to the piston hole and can be engaged with the rack tooth, and the pole is connected to the rack tooth. And urging means for urging in the engagement direction.

  In this case, when the piston moves together with the sleeve in the projecting direction with the tip of the pole engaged with the rack tooth of the sleeve, the rack tooth of the sleeve moves over the tip of the pole, thereby moving the piston. However, when the piston moves with the sleeve in the retracting direction, the sleeve's rack teeth are kept engaged with the tip of the pole so that the piston moves in the retracting direction. Movement is restricted.

However, in the conventional hydraulic tensioner, after the tensioner body that accommodates the piston is formed, a drilling process of the pole hole is required separately, or in order to form the pole hole, the center is separate from the mold for the tensioner body. There is a problem that a child is required and the manufacturing cost is increased accordingly.
US Pat. No. 5,304,099 (see FIG. 2)

  The problem to be solved by the present invention is to provide a tensioner body for a hydraulic tensioner that can reduce the manufacturing cost.

According to tensioner body according to the invention of claim 1, since the pawl hole extends in pull direction of the mold of the tensioner body, it is possible to mold the pole hole using a molding die of tensioner body As a result, the pole hole can be simultaneously formed when the tensioner body is formed. As a result, the drilling of the pole hole after the tensioner body molding and the core at the time of pole hole molding become unnecessary, and the manufacturing cost can be reduced.

In the tensioner body according to the second aspect of the present invention, the lower edge portions of the left and right opening portions of the pole hole extend to the vicinity of the center line of the piston hole. It can be surely exposed from the outside of the pole hole. Thus, when the reset of the ratchet mechanism at the time of maintenance such as engine timing chain system is required, by inserting a tool from the pole hole, it is possible to easily release the engagement between the pawl and the piston.

In tensioner body according to the invention of claim 3, the pole hole communicates with the left right sides of the opening. In this case, the pole holes are opened not only above the tensioner body but also on the left and right sides, and have open spaces, so that the pole holes can be formed more easily.

  A hydraulic tensioner according to a fourth aspect of the invention is configured using the tensioner body according to any one of the first to third aspects.

According to the molding method according to the invention of claim 5, at the time of molding the outer wall surface of the tensioner body, the inner wall surface of the pawl hole using a molding die during the molding is molded simultaneously, after tensioner body shaping pole The manufacturing cost can be reduced by eliminating the need for a core for hole drilling or pole hole forming.

  According to the molding method of the sixth aspect of the invention, the lower edges of the left and right openings of the pole hole extend to the vicinity of the center line of the piston hole. Similarly, the engaging portion between the pole and the piston can be reliably faced from the outside of the pole hole. Thus, when the ratchet mechanism needs to be reset during maintenance or the like, the engagement state between the pole and the piston can be easily released using the pole hole.

According to the molding method according to the invention of claim 7, since the pawl hole is in communication with the left right sides of the opening, as in the invention of claim 3, a space that Paul hole is opened This makes it easier to form pole holes.

According to the present invention, since the pawl hole extends in pull direction of the mold of the tensioner body, it is possible to mold the pole hole using a mold of the tensioner body, thereby forming the tensioner body Sometimes pole holes can be formed at the same time. As a result, the drilling of the pole hole after the tensioner body molding and the core at the time of pole hole molding become unnecessary, and the manufacturing cost can be reduced.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
1 is an overall perspective view of a hydraulic tensioner employing a tensioner body according to an embodiment of the present invention, FIG. 2 is an enlarged perspective view of a pole hole portion of the tensioner body, and FIG. 3 is an enlarged front view of the pole hole portion of the hydraulic tensioner. FIG, 4 is a diagram for explaining the molding die at the time of tensioner body molding.

  As shown in FIGS. 1 and 2, a hydraulic tensioner 1 includes a tensioner body 2 having a piston hole 2a with one end opened, and a chain (not shown) that is slidably inserted into the piston hole 2a of the tensioner body 2. And a pole 5 having a tooth portion 5a engaged with a rack tooth 3b formed on a part of the outer peripheral surface of the piston 3 on the lower surface.

  Although not shown, a piston spring that biases the piston 3 in a direction in which the piston 3 protrudes from the piston hole 2a is contracted in the piston hole 2a of the tensioner body 2. In the tensioner body 2, a fluid chamber (not shown) is formed from the inner wall surfaces of the piston 3 and the piston hole 2 a, and an external pressurized fluid source (not shown) enters the fluid chamber at the bottom of the tensioner body 2. An introduction hole (not shown) for introducing engine oil as a working fluid is formed. The tensioner body 2 is formed with bolt holes 20 and 21 into which mounting bolts for mounting the hydraulic tensioner 1 in, for example, an engine are inserted.

  The tensioner body 2 is formed with a pole hole 2b penetrating the tensioner body 2 in a direction orthogonal to the direction in which the piston hole 2a is disposed. The pole hole 2b communicates with the piston hole 2a.

  As shown in FIG. 3, when the horizontal direction (front-rear direction) in the figure is the X direction, the vertical direction (left-right direction) in the figure is the Y direction, and the vertical direction (vertical direction) is the Z direction, the piston hole 2a The piston 3 extends in the X direction. The pole hole 2b extends in the Y direction and also extends upward in the Z direction in this embodiment, that is, the pole hole 2b opens left and right and upward. The lower edges of the openings on the left and right sides of the pole hole 2b extend to the vicinity of the center line C of the piston hole 2a.

  The opening of the pole hole 2b is covered with a pole retainer 6 (see the dashed line in FIG. 3). The pole retainer 6 is bent in a U shape so as to cover the left and right openings and the upper opening of the pole hole 2b. A pole spring 7 is provided above the pole 5 inside the pole retainer 6. The pole spring 7 urges the pole 5 toward the piston 3 so that the tooth portion 5 a of the pole 5 engages with the rack tooth 3 b of the piston 3.

  As shown in FIGS. 1 to 3, the tensioner body 2 is provided with a pair of standing wall portions 25, 26 on the front and rear end sides of the opening above the pole hole 2 b, and a lower portion of each standing wall portion 25, 26. Engaging recesses 25a and 26a are respectively formed in the. Part of the pole retainer 6 is provided with an engaging projection (not shown) that can be detachably engaged with the engaging recesses 25a, 25a of the standing wall portions 25, 26 (see FIG. 3).

  A through hole 23 is formed in the tensioner body 2 in the vicinity of the opening of the piston hole 2a. The through-hole 23 is for holding the piston 2 in a retracted state by inserting a retaining pin (not shown) during transportation of the tensioner, and the inserted retaining pin is a head of the piston 3. It is possible to engage with a locking groove (not shown) formed in.

Next, the operation of the hydraulic tensioner configured as described above will be briefly described.
During operation, the resultant force of the spring force of the piston spring and the hydraulic pressure in the fluid chamber acts on the chain from the piston tip surface 3c via a tensioner arm (not shown), so that the chain tension is maintained. Yes.

  In addition, when a pressing force is applied from the chain to the piston tip surface 3c under a situation where sufficient fluid pressure is not applied in the fluid chamber, such as when the engine is started, the rack teeth 3b on the outer periphery of the piston The piston 3 moves backward together with the pole 5 while maintaining the engaged state with the teeth 5a of the belt 5, and the rear end surface of the pole 5 comes into contact with the side wall surface of the pole hole 2b. Stops.

  Next, a molding die for molding the tensioner body 2 will be described with reference to FIG. FIG. 4 shows a cross section in the Y direction passing through the lowermost ends of the openings on the left and right sides of the pole hole 2b in the tensioner body 2. In the figure, reference numerals 10A and 10B denote molding dies, which are provided so as to be close to and away from each other in the Y direction. Reference numeral 11 denotes a core for forming the piston hole 2 a of the tensioner body 2.

  As can be seen from FIG. 4, each of the molding dies 10A and 10B enters the pole hole 2b of the tensioner body 2 and is provided so as to mold the inner wall surface of the pole hole 2b. In other words, the pole hole 2b extends in the drawing direction of the molding dies 10A and 10B (arrow direction in the figure).

  Thus, since the pole hole 2b extends in the pulling direction of the molds 10A and 10B of the tensioner body 2, the pole hole 2b can be molded using the molds 10A and 10B of the tensioner body 2. As a result, the pole hole 2b can be formed simultaneously when the tensioner body 2 is formed. As a result, the punching process of the pole hole 2b after the tensioner body molding and the core at the time of pole hole molding become unnecessary, and the manufacturing cost can be reduced.

In this case, the lower edge of the opening on both the left and right sides of the pole hole 2b extends to the vicinity of the center line C of the piston hole 2a. It is possible to reliably face the outside of the hole 2b. Thus, when the reset of the ratchet mechanism at the time of maintenance such as engine timing chain system is required, by inserting a tool from the pole hole 2b, it is possible to easily release the engagement between the pawl 5 and the piston 3 .

Further, in this case, the pole hole 2b is opened not only above the tensioner body 2 but also on both the left and right sides , and is an open space, so that the pole hole 2b can be formed more easily. Become.

1 is an overall perspective view of a hydraulic tensioner employing a tensioner body according to an embodiment of the present invention. It is a perspective enlarged view of the pole hole part of a tensioner body (FIG. 1). It is a front enlarged view of the pole hole part of a hydraulic tensioner (FIG. 1). It is a figure for demonstrating the shaping die at the time of shaping | molding of a tensioner body (FIG. 1).

1: Hydraulic tensioner

2: Tensioner body 2a: Piston hole 2b: Pole hole

3: Piston 3b: Rack teeth

5: Paul 5a: Teeth

10A, 10B: Mold

Claims (7)

A tensioner body for a hydraulic tensioner for slidably supporting a piston that abuts on a chain to generate tension in a longitudinal direction,
A piston hole for accommodating the piston, extending in the front-rear direction and opening at one end;
A pole hole extending in the left-right direction perpendicular to the direction in which the piston hole is disposed and communicating with the piston hole, and penetrating the tensioner body in the left-right direction and upward ,
The pole hole extends in the drawing direction of a molding die for molding the outer wall surface of the tensioner body.
A tensioner body for a hydraulic tensioner characterized by that. In claim 1,
The lower edge of the opening on both the left and right sides of the pole hole extends to the vicinity of the center line of the piston hole,
A tensioner body for a hydraulic tensioner characterized by that. In claim 1 or 2,
The pole hole communicates with the left right sides of the opening,
A tensioner body for a hydraulic tensioner characterized by that.   A hydraulic tensioner using the tensioner body according to any one of claims 1 to 3. The chain abuts have a piston bore for slidably supported a piston to cause tension, the tensioner body communicates with the arrangement direction and extend in the horizontal direction perpendicular and the piston bore of the piston bore In the method of forming a tensioner body for a hydraulic tensioner having pole holes penetrating in the left-right direction and upward ,
During molding of the outer wall surface of the tensioner body, the inner wall surface of the pawl hole using a molding die during the molding is simultaneously molded,
A method for forming a tensioner body for a hydraulic tensioner, characterized in that: In claim 5,
The lower edge of the opening on both the left and right sides of the pole hole extends to the vicinity of the center line of the piston hole,
A method for forming a tensioner body for a hydraulic tensioner, characterized in that: In claim 5 or 6,
The pole hole communicates with the left right sides of the opening,
A method for forming a tensioner body for a hydraulic tensioner, characterized in that:

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