Spanner

Abstract

Tensioner (10), comprising: a piston (20) with a piston hole (21) open at a rear; a housing (30) with a piston receiving hole (31) open at a front and receiving the piston (20); a spring (50) received in an oil pressure chamber (11) formed between the piston (20) and the piston receiving hole (31) to expand and contract and to push the piston (20) towards the front; and a locking mechanism (60) that prevents the piston (20) from springing forward towards the front. wherein the spring (50) has a first end (51) and a second end (52), wherein the locking mechanism (60) includes a first locking piece (70) formed separately from the piston (20) and a second locking piece (80), wherein the first locking element (70) comprises a first spring retainer (71) arranged at the first end (51) of the spring (50), a bolt part (72) extending from the first spring retainer (71) towards the second end (52), and a locking projection (73) formed on the bolt part (72), wherein the second locking element (80) comprises a second spring retainer (81) arranged at the second end of the spring (50), a tubular part (82) extending from the second spring retainer (81) towards the first end (51), and a movement-limiting part (85) which restricts the movement of the locking projection (73) towards the first end (51) and is formed on the tubular part (82), wherein the bolt part (72) is inserted into the tubular part (82), wherein the locking projection (73) formed on the bolt part (72) and the movement limiting part (85) formed on the tubular part (82) lie radially inside the spring (50) and wherein the locking projection (73) and the movement restriction part (85) are designed together for a triggerable intervention.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The present invention relates to a tensioner that exerts a suitable tension on a running chain, belt or the like. 2. Description of the related technology

[0002] To maintain appropriate tension on a chain or similar component, it is common practice to use a tensioner. For example, a well-known chain guidance mechanism uses a tensioner to pre-tension a tensioner lever for the sliding guidance of a drive chain, such as an endless roller chain, which runs over the respective sprockets of a crankshaft and a camshaft in an engine compartment, in order to maintain the appropriate tension of the chain or similar component.

[0003] A known tensioner 510 used in such a chain guide mechanism includes, as in Fig. Figure 10 shows a piston 520 with a piston hole open at the rear, a housing 530 with a piston receiving hole open at the front to receive the piston 520, and a spring which is received in an oil pressure chamber formed between the piston 520 and the housing 530 in order to be able to expand and contract and to push the piston 520 towards the front (see, for example, Japanese Patent Application No. 2004-44749).

[0004] Since it is necessary to prevent the piston 520 from exiting forward before it is set on a chain or the like, such a tensioner 510 requires a safety mechanism that prevents the piston 520 from exiting forward.

[0005] A locking mechanism which is pivotably attached to the housing 530 via a locking pin 561 supported on the housing 530, as shown in Fig. The locking mechanism shown in Figure 10 is widely used. It includes a ratchet wheel 562 which can engage with the piston 520, a locking lever 563 which is attached to one end of the locking pin 561, and a locking pin 564 extending through the locking lever 563 and the housing 530 to block the rotation of the locking lever 563, thereby blocking the rotation of the ratchet wheel 562.

[0006] Another example of a locking mechanism has a piston locking hook 566, which is pivotally mounted on a pivot pin 565 attached to the housing 530, and engages with a locking pin 567 attached to the piston 520, as shown in Fig. 11 shown to prevent the piston 520 from exiting forward (see, for example, Japanese patent specification no. 2003-35343).

[0007] Further relevant prior art relating to the present invention is described in DE 14 50 801 B, DE 43 16 878 A1 and DE 195 33 725 A1. BRIEF SUMMARY OF THE INVENTION

[0008] One problem with the in Fig. 10 and Fig. The advantage of the clamps shown in Figure 11 is that these clamps 510 require sufficient installation space to avoid unwanted contact with adjacent components of the engine block or control housing, since the components of the locking mechanisms are located outside the housing.

[0009] Another problem with the in Fig. 10 and Fig. The reason for the 11 clamps shown is that the piston and housing require machining, such as attaching additional parts and the like, which leads to an increase in the production costs of the clamp.

[0010] The present invention solves these problems and it is an object of the invention to provide a clamping device which, with a simple design, enables a reduction in the installation space for the clamping device and a reduction in production costs.

[0011] The present invention solves the above problems by providing a tensioner comprising: a piston with a piston hole open at a rear; a housing with a piston receiving hole open at a front and receiving the piston; a spring contained in an oil pressure chamber formed between the piston and the piston receiving hole, enabling it to expand and contract and push the piston forward; and a locking mechanism that prevents the piston from springing forward. The spring comprises a first end arranged on a first side in a front-to-rear direction and a second end arranged on a second side in a front-to-rear direction. The locking mechanism comprises a first locking element formed separately from the piston and a second locking element.The first locking element comprises a first spring retainer, located on the first side of the first end of the spring, and a restricted portion in the form of a locking projection. The second locking element comprises a second spring retainer, located on the second side of the second end of the spring, and a movement-limiting portion that restricts the movement of the locking projection toward the first side. The locking projection and the movement-limiting portion are designed to engage with each other in a releasable manner.

[0012] According to a first aspect of the present invention, the first locking element comprises a first spring retainer arranged on the first side of the first end of the spring and a locking projection. The second locking element comprises a second spring retainer arranged on the second side of the second end of the spring and a movement-limiting element that restricts the movement of the locking projection toward the first side. The locking projection and the movement-limiting element are designed for releasable engagement with each other, which is why the first locking element and the second locking element are located inside the oil pressure chamber and do not need to be provided outside the tensioner. This avoids unwanted contact between adjacent components of the engine block or the like and the locking elements, thus reducing the installation space required for the tensioner.

[0013] Since the first locking piece and the second locking piece are located in the oil pressure chamber, no machining is required for the piston and the housing, thus avoiding an increase in the production costs of the clamp.

[0014] After attaching the first and second locking pieces to the spring, they can be handled as a single unit. This simplifies the design of the tensioner's mounting device and reduces the costs associated with its assembly.

[0015] Since the first and second locking pieces are located inside the oil pressure chamber, the volume inside the oil pressure chamber is reduced, making it possible to maintain the high pressure condition in the oil pressure chamber with a smaller amount of oil.

[0016] According to a further aspect of the present invention, the second locking element includes a release control cam formed on the second side opposite the movement-limiting element. This release control cam is designed to guide the locking projection circumferentially to an open position where the locking projection is not engaged by the movement-limiting element when the first locking element and the second locking element are moved closer together. By moving the piston backward, the first locking element and the second locking element can be moved closer together to disengage the locking projection from the movement-limiting element. The piston is therefore simply released from the locking position by the fact that the piston is pushed backward by the clamping lever or the like when the clamp is installed.It is also possible to prevent the piston locking mechanism from failing to release.

[0017] According to a further aspect of the present invention, the movement-limiting element has a curved profile for guiding the locking projection to a restraint, where the movement of the locking projection is restricted by the movement-limiting element when the first locking piece and the second locking piece are moved apart. When the first locking piece and the second locking piece are attached to the spring, the first locking piece and the second locking piece are moved closer together with the spring positioned between the first spring retainer and the second spring retainer to cause the locking projection to engage with the movement-limiting element. The compressed spring is subsequently released, so that the first locking piece and the second locking piece are moved apart by the spring force.The locking projection can therefore be reliably adjusted to the restricted position with a simple process.

[0018] According to the present invention, the locking projection and the movement-limiting element are arranged radially inside the spring. The first and second locking elements can therefore be positioned by utilizing the space within the spring. This avoids increasing the size of the oil pressure chamber while ensuring a large spring diameter.

[0019] According to the present invention, the first locking element comprises a bolt portion on which the locking projection is formed. The second locking element comprises a tubular portion on which the movement-limiting element is formed. The bolt portion is inserted into the tubular portion. This simple design can favorably maintain the alignment of the first and second locking elements relative to each other.

[0020] According to a further aspect of the present invention, the movement limitation element and the release control cam are formed by a slot in the tubular part of the second locking piece. The movement of the locking projection and the first locking piece can therefore be controlled efficiently and reliably with a simple design.

[0021] According to a further aspect of the present invention, at least part of a check valve is accommodated in the tubular part, on its second side, so that the check valve assembly, including the spring, the first locking element, and the second locking element, can be handled as a single unit. This reduces the costs associated with assembling the tensioner. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is an illustrative diagram showing a control system in which a tensioner according to a first embodiment of the present invention is incorporated; Fig. Figure 2 is an illustrative diagram showing the spanner; Fig. Figure 3 is a perspective view illustrating a spring and a safety mechanism; Fig. Figure 4 is a perspective exploded view illustrating the spring and the safety mechanism; Fig. 5A to Fig. 5C are diagrams that illustrate how the safety mechanism works; Fig. Figure 6 is a cross-sectional view illustrating a clamp according to a second embodiment of the present invention; Fig. Figure 7 is a perspective view illustrating a spring and a safety mechanism; Fig. Figure 8 is a perspective exploded view illustrating the spring and the safety mechanism; Fig. Figure 9 is a perspective exploded view illustrating a check valve assembly; Fig. 10 is a perspective view illustrating a spanner of the related technique; and Fig. Figure 11 is an illustrative diagram showing another spanner of the related technique. DESCRIPTION OF PREFERRED EXECUTION FORMS

[0022] Below, a clamping device 10 according to a first embodiment of the present invention is described with reference to the drawings.

[0023] Firstly, the tensioner 10 is installed in a chain power transmission used in a control system or similar of an automotive engine. As in Fig. As shown in Figure 1, the tensioner is attached to an engine block (not shown) to apply appropriate tension to the loose side of a drive chain CH, which runs over several sprockets S1 to S3 via a tensioner lever G to reduce vibrations during driving.

[0024] The Spanner 10 includes, as in Fig. Figure 2 shows a piston 20 with a piston hole 21 open at a rear, a housing 30 with a piston receiving hole 31 open at a front and receiving the piston 20, a check valve assembly 40 arranged on the side of a lower part 32 of the housing 30, a spring 50 in the form of a coil spring received in an oil pressure chamber 11 formed between the piston 20 and the piston receiving hole 31, in order to be able to expand and contract and push the piston 20 towards the front, and a locking mechanism 60 which temporarily prevents the piston 20 from springing forward towards the front.

[0025] The following describes various components of the clamping device 10 with reference to the drawings.

[0026] The piston 20 is made of metal, such as iron or the like, in the form of a cylinder with a base and is inserted into the piston mounting hole 31 so that it can move back and forth in the front-to-back direction, as shown in Fig. 2 shown.

[0027] The housing 30 is made of aluminum alloy or synthetic resin and the like, and includes, as in Fig. 2 shown, the cylindrical piston receiving hole 31, which is open at the front, a lower part 32 formed at the rear and an oil supply hole 33 formed in the lower part 32 to extend through an outer wall of the housing 30 into the piston receiving hole 31.

[0028] The check valve unit 40 allows the oil to flow from the outside through the oil supply hole 33 into the oil pressure chamber 11 and prevents the oil from flowing out of the oil supply hole 33.

[0029] The check valve unit 40 comprises a ball seat 41, a round sealing ball 42 which can sit on the ball seat 41 in close contact with it, a holder 43 which is arranged on the front of the sealing ball 42 to limit the movement of the sealing ball 42, and a ball spring 44 which pushes the sealing ball 42 towards the ball seat 41, as shown in Fig. 2 shown. The ball spring 44 does not necessarily need to be provided.

[0030] The spring 50 is arranged with one end at the rear of the bottom of the piston hole 21 (a front part of the piston 20) and with the other end at the front of the check valve unit 40 (holder 43), as shown in Fig. 2 shown. The spring 50 is arranged with a first end 51 on a first side in the direction from front to back (in this embodiment the front) and with a second end 52 on a second side in the direction from front to back (in this embodiment the back).

[0031] The locking mechanism 60 is designed to temporarily prevent the piston 20 from springing forward, thus keeping the spring 50 compressed in the front-to-back direction. As in Fig. 2 to Fig. As shown in Figure 4, the locking mechanism consists of a first locking piece 70 and a second locking piece 80 made of synthetic resin or metal or the like.

[0032] The first safety piece 70 is a single piece, as in Fig. 2 to Fig. Figure 4 shows a disc-like first spring retainer 71, which is arranged on the first side (in this embodiment the front) of the first end 51 of the spring 50, a column-shaped bolt part 72 which extends from the first spring retainer 71 towards the second side, and a column-shaped locking projection 73 which is formed as a round projection on an outer circumferential surface of the bolt part 72.

[0033] The first spring holder 71 is arranged in contact with the lower end of the piston hole 21.

[0034] The second locking piece 80 is a single piece, as in Fig. 2 to Fig. Figure 4 shows a ring-shaped second spring holder 81, which is arranged on the second side (in this embodiment the rear) of the second end 52 of the spring 50, and a cylindrical tubular part 82, which extends from the second spring holder 81 to the first side.

[0035] The second spring retainer 81 is arranged in contact with the check valve unit 40 (retainer 43). The second spring retainer 81 extends radially further outwards than the outer circumferential surface of the tubular part 82.

[0036] In the middle of the second spring holder 81, a hole extending in the direction from front to back (not shown) is formed, so that oil supplied from outside the housing 30 via the oil supply hole 33 and the check valve unit 40 is supplied through this hole and a hollow part of the tubular part 82 into the oil pressure chamber 11.

[0037] The tubular part 82 is formed with a through slot 83 extending from an edge on the first side of the tubular part 82 in a front-to-back direction to the second side, and a movement-limiting slot 84 continuing with the through slot 83, as shown in Fig. 4 shown, trained.

[0038] The through-slot 83 extends with a predetermined width to allow the locking projection 73 to pass through, between the outer circumferential surface and the inner circumferential surface of the tubular part 82, as shown in Fig. 4 shown. A part on the first side of the through slot 83 has a chamfered shape, so that the width increases towards the first side.

[0039] The movement restriction slot 84 extends diagonally from the end on the second side (rear) of the passage slot 83 relative to the circumferential direction and in a front-to-back direction towards the first side (front) and away from the passage slot 83, as shown in Fig. 4 shown.

[0040] The movement restriction slot 84 extends with a predetermined width to allow the locking projection 73 to pass through and be received, between the outer circumferential surface and the inner circumferential surface of the tubular part 82.

[0041] An inner rim on the first side of the movement-limiting slot 84 acts as a movement-limiting element 85, which restricts the movement of the locking projection 73 of the first locking piece 70 towards the first side, as shown in Fig. 4 shown.

[0042] This movement restriction part 85 has a curve profile for guiding the locking projection 73 to a restriction position where the movement of the locking projection is restricted by the movement restriction part 85 when the first locking piece 70 and the second locking piece 80 are moved apart.

[0043] More specifically, the movement restriction part 85 extends diagonally towards the first side (front side) and away from the through slot 83 relative to the circumferential direction and the front-to-back direction, as shown in Fig. 4 shown, designed to guide the locking projection 73 to the limiting position at the end of the movement limiting slot 84 when the first locking piece 70 and the second locking piece 80 are moved apart by the force of the spring 50.

[0044] The locking projection 73 and the movement restriction part 85 are designed to allow for triggerable intervention together.

[0045] An inner edge of the second side of the motion restriction slot 84 opposite the motion restriction part 85 in the front-to-back direction acts as a trigger control curve 86.

[0046] This release control cam 86 is designed to guide the locking projection 73 in the circumferential direction to an open position where the locking projection is not locked by the movement restriction part 85 when the first locking piece 70 and the second locking piece 80 are moved closer together.

[0047] More specifically, the release control cam 86, which extends diagonally towards the first side (front side) and away from the through slot 83 relative to the circumferential direction and the direction from front to back, is designed to guide the locking projection 73 to the open position, i.e. an end position on the second side of the through slot 83, when the first locking piece 70 and the second locking piece 80 are moved towards each other.

[0048] The process of attaching the first locking piece 70 and the second locking piece 80 to the spring 50 is described below.

[0049] First, as in Fig. 5C shows the tubular part 82 of the second locking piece 80 being inserted into the spring 50 from the side of the second end 52 and the bolt part 72 of the first locking piece 70 being inserted into the spring 50 from the side of the first end 51.

[0050] Next, with the spring 50 located between the first spring retainer 71 of the first locking piece 70 and the second spring retainer 81 of the second locking piece 80, the first locking piece 70 and the second locking piece 80 are moved closer together in a front-to-back direction to compress the spring 50, and the bolt part 72 is inserted into the tubular part 82 from the first side, with the locking projection 73 positioned in the through slot 83.

[0051] Next, as in Fig. As shown in Figure 5B, the first locking piece 70 and the second locking piece 80 are rotated relative to each other so that the locking projection 73 is positioned in the movement-limiting slot 84 after the first spring holder 71 and the second spring holder 81 have been moved closer to each other until the locking projection 73 comes close to the end on the second side of the through slot 83.

[0052] When the stress on the compressed spring 50 is removed, the spring 50 is elastically returned to its original position and expands, causing the first locking piece 70 and the second locking piece 80 to move apart, and the locking projection 73 is guided by the movement-limiting part 85 to the limiting position at the end of the movement-limiting slot 84, as shown in Fig. 5A is shown. At this point, the first fuse piece 70 and the second fuse piece 80 rotate relative to each other.

[0053] The engagement between the locking projection 73 and the movement restriction part 85 then holds the first locking piece 70 and the second locking piece 80 in their positions relative to each other in the front-to-back direction, so that the spring 50 is held compressed, and the spring 50, the first locking piece 70 and the second locking piece 80 can thus be handled as a unit.

[0054] Next, the procedure for releasing the locking mechanism 60, which prevents the piston 20 from jumping forward, is described below.

[0055] First, as in Fig. 5A shows the spanner 10 at a predetermined position, as shown in Fig. 1 shown, installed, wherein the compressed spring 50, the first locking piece 70 and the second locking piece 80 are assembled as a unit which is arranged in the oil pressure chamber 11.

[0056] When installed, the piston 20 is pushed backward by the tensioning lever G, causing the first locking piece 70 and the second locking piece 80 to move closer together. This allows the locking projection 73 to be guided by the release control cam 86 to the open position, which is the end position on the second side of the through slot 83. That is, the locking projection 73 and the movement limiting element 85 disengage from each other automatically. At this point, the first locking piece 70 and the second locking piece 80 rotate relative to each other.

[0057] Next, when the piston 20 is prevented from being pushed backward, the spring 50 is elastically reset and expands, and the piston 20 is pushed by the spring 50 to spring forward.

[0058] When the spring 50 extends, the first spring retainer 71 (the first locking piece 70) can be subjected to a rotational force from the first end 51 of the spring 50 (which, viewed from above, acts clockwise if the spring 50 is left-handed, as in this embodiment). The movement-limiting slot 84 is positioned by this rotational force applied to the first locking piece 70 relative to the through-slot 83 such that the locking projection 73 does not re-enter the movement-limiting slot 84 (in this embodiment, viewed from above, the movement-limiting slot 84 is clockwise behind the through-slot 83).

[0059] Next, a clamping device 10 according to a second embodiment of the present invention is described with reference to Fig. 6 to Fig. 9 described. The second embodiment is partly exactly the same as the first embodiment already described and, apart from the differences, the description of its configurations is therefore omitted.

[0060] In the second embodiment, as in Fig. As shown in Figure 8, at least a part of the check valve unit 40 (in this embodiment the entire check valve unit 40) is received in the tubular part 82 on the second side (in this embodiment the rear) of the second locking piece 80 and in the hole formed in the middle of the second spring holder 81 (not shown).

[0061] The check valve unit 40 can also be handled as a unit with the spring 50, the first locking device 70 and the second locking device 80.

[0062] The check valve unit 40 can be attached to the second locking piece 80. Alternatively, the check valve unit 40 can only be accommodated in the second locking piece 80 and not attached to the second locking piece 80.

[0063] For example, although the tensioner in the above embodiments was described as a component to be installed in a control system of an automotive engine, the purpose of the tensioner is not limited to this specific application.

[0064] Although the tensioner in the above embodiments was described as a component that exerts tension on a drive chain with a tensioner lever, the piston can directly guide the drive chain with a distal end of it in a sliding manner in order to exert tension force on the drive chain.

[0065] The tensioner does not necessarily have to be applied to a power transmission mechanism with a drive chain, but can also be used for similar power transmission mechanisms that use belts, ropes and the like, and can be applied in various industrial fields where it is required that tension force be applied to an elongated element.

[0066] Although the housing receiving the piston is described as the component known as a clamping body, which in the embodiments described above is attached to an engine block or the like, the housing is not limited to the specific shape described above and can be a cylindrical component known as a sleeve, which is inserted into a body hole formed in the clamping body.

[0067] Although the first locking piece and the second locking piece are described as being arranged on the front and back respectively in the embodiments described above, the first locking piece and the second locking piece can be arranged on the back and the front respectively.

[0068] Although the method for triggering the engagement of the first and second locking pieces in the embodiments described above uses the locking projection of the first locking piece and the movement restriction part and the release control cam of the second locking piece, the method for triggering the engagement of the first and second locking pieces is not limited to that described above and any other method can be used.

[0069] Although the first locking element is described as having a bolt-like portion in the embodiments described above, the first locking element is not limited to the specific shape described above. For example, the first locking element may have a tubular portion extending from the first spring retainer to the second side, and this tubular portion may be arranged radially inside or outside the tubular portion of the second locking element.

[0070] Although the locking projection of the first locking piece and the movement-limiting part (and the release control cam) of the second locking piece are described as being arranged radially inside the spring in the embodiments described above, this locking projection and movement-limiting part (and the release control cam) can be arranged radially outside the spring.

Claims

[1] Tensioner (10) comprising: a piston (20) with a piston hole (21) open at a rear; a housing (30) with a piston receiving hole (31) open at a front and receiving the piston (20); a spring (50) received in an oil pressure chamber (11) formed between the piston (20) and the piston receiving hole (31) to expand and contract and to push the piston (20) towards the front; and a locking mechanism (60) that prevents the piston (20) from springing forward towards the front, wherein the spring (50) has a first end (51) and a second end (52), wherein the locking mechanism (60) includes a first locking piece (70) formed separately from the piston (20) and a second locking piece (80), wherein the first locking element (70) comprises a first spring retainer (71) arranged at the first end (51) of the spring (50), a bolt part (72) extending from the first spring retainer (71) towards the second end (52), and a locking projection (73) formed on the bolt part (72), wherein the second locking element (80) comprises a second spring retainer (81) arranged at the second end of the spring (50), a tubular part (82) extending from the second spring retainer (81) towards the first end (51), and a movement-limiting part (85) which restricts the movement of the locking projection (73) towards the first end (51) and is formed on the tubular part (82), wherein the bolt part (72) is inserted into the tubular part (82), wherein the locking projection (73) formed on the bolt part (72) and the movement limiting part (85) formed on the tubular part (82) lie radially inside the spring (50) and wherein the locking projection (73) and the movement restriction part (85) are designed together for a triggerable intervention. [2] Spanner (10) according to claim 1, wherein the second safety element (80) includes a release control cam (86) which is formed at the second end (52) opposite the movement restriction element (85), and the release control cam (86) is designed to guide the restricted part in a circumferential direction to an open position, where the locking projection (73) is not locked by the movement restriction part (85) when the first locking piece (70) and the second locking piece (80) are moved closer together. [3] Tensioner (10) according to claim 1 or 2, wherein the movement restriction part (85) has a curve profile that guides the locking projection (73) to a restriction position where the movement of the locking projection (73) is restricted by the movement restriction part (85) when the first locking piece (70) and the second locking piece (80) are moved apart. [4] Tensioner (10) according to one of claims 1 to 3, wherein the locking projection (73) is designed as a round projection on an outer circumferential surface of the bolt part (72) and the tubular part (82) includes a through slot (83) extending from an edge of the tubular part (82) at the first end (51) to the second end (52), and a movement-limiting slot (84) that is continued with the through slot (83), an inner edge of the movement restriction slot (84) on the side of the first end (51) functions as a movement restriction part (85) and an inner edge of the motion restriction slot (84) on the side of the second end (52) acts as a trigger control curve (86). [5] Tensioner (10) according to one of claims 1 to 4, wherein at least a part of a check valve unit (40), which allows oil to flow into the oil pressure chamber (11) and prevents the oil from flowing out of the oil pressure chamber (11), is received in the tubular part (82), at the second end (52).

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