JP4084487B2 - Hydraulic auto tensioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic auto tensioner for automatically applying an appropriate tension to a transmission member such as an endless annular flat belt, a V belt, a toothed belt, or a chain.
[0002]
[Prior art]
As a conventional hydraulic auto tensioner, the one described in JP-T-2-500210 is known. 11 and 12 show the structure described in the publication, in which a V-belt 1 is wound around a pulley 2 and an idler pulley 3. The idler pulley 3 is pivotably attached to the tip of the arm 4, and the base end of the arm 4 is pivotally attached to the shaft portion 5. A hydraulic auto tensioner 50 is connected to the center of the arm 4.
[0003]
The hydraulic auto tensioner 50 includes a bottomed cylindrical casing 51, a cylinder 52 fitted in the casing 51, a piston 53 slidably entered into the cylinder 52 through an opening end of the casing 51, and a casing A seal ring 54 is provided at the opening end of 51 and is in sliding contact with the piston 53, and the upper end of the piston 53 is connected to the arm 4. The high pressure oil chamber 55 pressed by the piston 53 in the cylinder 52 and the low pressure oil chamber 56 between the cylinder 52 and the casing 51 communicate with each other via a check valve 57 and a passage 58 below the cylinder 52, and the passage 58 Then, the oil flows from the low pressure oil chamber 56 to the high pressure oil chamber 55 and communicates via the clearance 59 between the cylinder 52 and the piston 53, and the oil flows from the high pressure oil chamber 55 to the low pressure oil chamber 56 via the clearance 59. It comes to flow.
[0004]
An engagement ring 60 is fitted in the middle of the piston 53, and a spring seat upper 61 that engages with the engagement ring 60 from below is loosely fitted. The spring seat upper 61 abuts against a lid 62 fixed by caulking to the opening end of the casing 51 so as not to come off, and the seal ring 54 is attached to the inner periphery of the lid 62. In the low pressure oil chamber 56, a return spring 64 is mounted between a spring seat lower 63 integrally formed at the lower part of the cylinder 52 and the spring seat upper 61, and the return spring 64 includes the spring seat upper 61 and the engagement ring 60. The piston 53 is urged in the cylinder withdrawal direction (upward in the figure) via
[0005]
[Problems to be solved by the invention]
However, in the hydraulic auto tensioner 50, the casing 51 is formed in a cylindrical shape, and the high-pressure oil chamber 55 at the center of the casing 51 and the annular low-pressure oil chamber 56 around the outer periphery thereof are arranged concentrically. The outer diameter dimension of the casing 51 was large. Thus, if the outer diameter dimension (thickness) of the casing 51 is uniformly large in the width direction and the depth direction, the hydraulic auto tensioner 50 cannot be mounted when the space of the tensioner mounting portion is small. was there.
[0006]
An object of the present invention is to solve the above-mentioned problem and to make the system compact in a certain direction of thickness (represented as a depth direction in the present specification), and a conventional hydraulic auto tensioner. It is to provide a hydraulic auto tensioner that can be installed even in a narrow space that cannot be installed.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a hydraulic auto tensioner according to the present invention has a casing formed into a shape having a small depth and a width larger than the depth, and is pressed by a plunger in the width direction of the casing. And a low-pressure oil chamber that can communicate with the high-pressure oil chamber are arranged in parallel, separated by a partition wall of the casing, and oil is provided in one direction from the low-pressure oil chamber to the high-pressure oil chamber at a lower portion of the partition wall. An oil passage through which oil flows is formed, and an oil hole through which oil leaked from the high pressure oil chamber flows into the low pressure oil chamber is formed in the upper portion of the partition wall, and the low pressure oil chamber is provided in the casing. The push member is slidably moved vertically into the upper portion of the bottomed hole, and the upper end of the push member is formed on the lower surface of the pressure-receiving portion protruding from the upper portion of the plunger. The lower surface of the push member Return spring between the inner bottom surface of the hole in the bottom is mounted in a compressed state.
[0008]
Here, the terms “depth” and “width” of the casing are used to relatively express a specific direction of thickness and a direction orthogonal thereto, and are determined as depth or width, respectively. There is no direction. Moreover, the small depth of the casing means that a high pressure oil chamber and a low pressure oil chamber can be provided and are small enough to ensure strength, and do not have an unnecessary size. It is preferable to set the limit.
[0009]
Moreover, it is preferable to arrange | position a high pressure oil chamber on the axial center extended in the longitudinal direction of a plunger from the center of the attaching part of a plunger.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, two embodiments embodying the hydraulic auto tensioner of the present invention will be described with reference to FIGS. The second embodiment is a reference example.
These hydraulic auto tensioners are general-purpose products for automatically applying an appropriate tension to transmission members such as an endless annular flat belt, a V belt, a toothed belt, and a chain. The structure between the hydraulic auto tensioner and the transmission member is not particularly limited, and can be used instead of the conventional hydraulic auto tensioner 50 as shown in FIG. 11, for example.
[0011]
[First embodiment]
First, the hydraulic auto tensioner 10 according to the first embodiment shown in FIGS. 1 to 5 has a small depth (perpendicular direction in FIG. 1 and FIG. 2 and vertical direction in FIGS. 3 to 5) and a width ( A casing 11 having a large shape (for example, 1.5 times to 3 times) (for example, an elliptical cross section) is provided. An annular collar 13 is rotatably provided via a dry bearing 14 at an attachment portion 12 (to other member) that is integrally formed on the right side of the lower surface of the casing 11 (to another member). Bottomed holes 15 a and 15 b having upper surfaces opened are formed on the right and left sides of the casing 11, respectively, and the holes 15 a and 15 b are separated by a partition wall 32.
[0012]
A bottomed inner cylinder 17 having an outer diameter substantially the same as the inner diameter is inserted and fixed in the right hole 15a. The inside of the inner cylinder 17 is a cylinder hole 17a, and a rod-like piston portion 18 provided at the lower end of the plunger 8 can slide up and down with a predetermined clearance 30 from the opening end of the hole 15a to the cylinder hole 17a. I have entered. An annular collar 13 is rotatably provided on a mounting portion 19 at the upper end of the plunger 8 via a dry bearing 14, and the collar 13 is connected to, for example, the arm 4 in FIG. A high pressure oil chamber 23 that is pressed by the plunger 8 is formed between the cylinder hole 17 a and the lower end surface of the piston portion 18. Since the high pressure oil chamber 23 is disposed on the axial center extending in the longitudinal direction of the plunger 8 from the center of the collar 13 of the mounting portion 19, no rotational moment is generated when the plunger 8 presses the high pressure oil chamber 23.
[0013]
A low pressure oil chamber 24 is formed in the lower portion of the left hole 15b. That is, the high-pressure oil chamber 23 and the low-pressure oil chamber 24 are arranged in parallel in the width direction of the casing 11, and an appropriate amount of oil is put in each of them. The high pressure oil chamber 23 and the low pressure oil chamber 24 are provided through a communication hole 26 provided in the bottom wall of the inner cylinder 17, a check valve 25 provided on the high pressure oil chamber 23 side, and a lower portion of the partition wall 32. The oil passage 16 can communicate with the high-pressure oil chamber 23 in one direction from the low-pressure oil chamber 24. The high-pressure oil chamber 23 and the low-pressure oil chamber 24 include a clearance 30 between the inner cylinder 17 and the piston portion 18, and oil holes 33 and 34 respectively penetrating the upper portion of the partition wall 32 and a push member 27 described later. Thus, oil can leak from the high pressure oil chamber 23 to the low pressure oil chamber 24.
[0014]
A push member 27 enters the upper portion of the left hole 15b so as to be slidable in the vertical direction, and the upper end of the push member 27 is a pressure-receiving portion 28 protruding leftward from the upper portion (attachment portion 19) of the plunger 8. It is in contact with the lower surface. A return spring 31 is mounted in a compressed state between the lower surface of the push member 27 and the inner bottom surface of the hole 15b inside the low pressure oil chamber 24, and the plunger 8 is retracted from the casing 11 via the push member 27. It is energizing (upward in the figure). A seal ring 20 slidably in contact with the plunger 8 and the push member 27 is mounted on the stepped portion on the inner periphery of the opening end of each hole 15a, 15b, and the seal ring 20 is fitted in a groove on the inner periphery of the opening end. The stopper ring 22 is locked from below so as not to come off. Reference numeral 21 denotes an insert fitting for the seal ring 20.
[0015]
As described above, the casing 11 is formed in a shape having a small depth and a width larger than the depth, and the high pressure oil chamber 23 and the low pressure oil chamber 24 are arranged in parallel in the width direction of the casing 11, thereby providing a thickness. Of these, the hydraulic auto tensioner 10 can be made compact in the depth direction, and can be installed in a space that cannot be installed with a conventional hydraulic auto tensioner.
[0016]
The operation when the auto tensioner 10 configured as described above is used as shown in FIG. 11, for example, will be described.
[0017]
The return spring 31 always urges the plunger 8 upward. When the tension of the V-belt 1 becomes excessive, the V-belt 1 allows the plunger 8 to be displaced upward by the return spring 31 via the idler pulley 3 and the arm 4, and as shown in FIG. The portion 18 is displaced in the direction of retreating from the inner cylinder 17. Then, the pressure in the high-pressure oil chamber 23 temporarily drops below the pressure in the low-pressure oil chamber 24, the check valve 25 is opened, and the oil in the low-pressure oil chamber 24 passes through the oil passage 16 from the communication hole 26 to the high-pressure oil chamber 23. Flows in. Thus, an appropriate tension is applied to the V belt 1.
[0018]
When the tension of the V belt 1 becomes excessive due to overload or the like, the V belt 1 strongly presses the plunger 8 downward via the idler pulley 3 and the arm 4. Then, as shown in FIG. 2, the oil in the high pressure oil chamber 23 leaks from the clearance 30 to the low pressure oil chamber 24 through the oil holes 33 and 34. Therefore, since the piston part 18 can be made to enter deeply into the inner cylinder 17, the tension of the V-belt 1 can be reduced, and at the same time, changes in the belt length can be absorbed (automatic adjustment).
[0019]
[Second Embodiment]
Next, the hydraulic auto tensioner 40 of the second embodiment shown in FIG. 6 to FIG. 10 forms the casing 11 in a cross-sectional drop shape with a small depth and a width larger than the depth (the depth is slightly larger on the right side). The diameter of the right hole 15a, the inner cylinder 17 and the piston portion 18 is increased, and a cylindrical recess 41 is formed in the piston portion 18 from the lower surface. The inside of the high-pressure oil chamber 23 and the top of the cylindrical recess 41 is formed. The point that the return spring 31 is mounted in a compressed state between the surface and the bottom wall of the inner cylinder 17, and the point that the push member 27 is omitted and the hole 15 b is closed with the lid 42 in accordance with this is the first implementation. It is different from the form.
[0020]
In addition, about the member, site | part, or method common to 1st embodiment, the same code | symbol as 1st embodiment is attached | subjected to FIGS. 6-10, and the description is not repeated. Also in this embodiment, the same effect can be obtained for the same reason as in the first embodiment.
[0021]
In addition, this invention is not limited to the said embodiment, For example, it can also be suitably changed and embodied as follows, for example in the range which does not deviate from the meaning of invention.
[0022]
(1) Divide the low-pressure oil chamber into two and arrange them in parallel on both sides of the high-pressure oil chamber.
[0023]
【The invention's effect】
As described above in detail, according to the hydraulic auto tensioner according to the present invention, it can be made compact in a certain direction of the thickness, and it is so narrow that it cannot be attached with the conventional hydraulic auto tensioner. It has an excellent effect that it can be installed in a space.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a hydraulic auto tensioner according to a first embodiment of the present invention, which is shown in a vertically cut state.
FIG. 2 is a cross-sectional view showing the compressed state of the hydraulic auto tensioner cut vertically at another position.
3 is a plan view of FIG. 1. FIG.
4 is a bottom view of FIG. 1. FIG.
FIG. 5 is a cross-sectional view taken along line VV in FIG.
FIG. 6 is a cross-sectional view of the hydraulic auto tensioner according to the second embodiment of the present invention, which is shown in a vertically cut state.
FIG. 7 is a cross-sectional view showing the compressed state of the hydraulic auto tensioner cut vertically at another position.
FIG. 8 is a plan view of FIG. 6;
FIG. 9 is a bottom view of FIG. 6;
10 is a cross-sectional view taken along line XX in FIG.
FIG. 11 is a schematic view showing an example of use of a hydraulic auto tensioner.
FIG. 12 is a partially broken front view showing a conventional hydraulic auto tensioner.
[Explanation of symbols]
8 Plunger 10 Hydraulic auto tensioner 11 Casing 12 Mounting part 13 Collar 15a, 15b Hole 16 Oil passage 17 Inner cylinder 17a Cylinder hole 18 Piston part 19 Mounting part 23 High pressure oil chamber 24 Low pressure oil chamber 25 Check valve 26 Communication hole 27 Push Member 28 Pressure-receiving part 30 Clearance 31 Return spring 32 Partitions 33, 34 Oil hole 40 Hydraulic auto tensioner 41 Cylindrical recess 42 Lid

Claims (2)

The casing is formed into a shape having a small depth and a width wider than the depth, and a high pressure oil chamber pressed by a plunger in the width direction of the casing and a low pressure oil chamber capable of communicating with the high pressure oil chamber Are arranged in parallel, separated by a partition wall, and an oil passage through which oil flows in one direction from the low-pressure oil chamber to the high-pressure oil chamber is provided in a lower portion of the partition wall, and the high-pressure oil is disposed above the partition wall. Through which oil leaked from the chamber flows into the low-pressure oil chamber,
The low-pressure oil chamber is formed at a lower portion of a bottomed hole provided in the casing, and a push member enters the upper portion of the bottomed hole so as to be slidable up and down, and an upper end of the push member is at the plunger A hydraulic auto-tensioner that abuts the lower surface of the pressure-receiving portion projecting from the upper portion of the first member and that has a return spring mounted in a compressed state between the lower surface of the push member and the inner bottom surface of the bottomed hole .   The hydraulic auto tensioner according to claim 1, wherein the high-pressure oil chamber is disposed on an axis extending in the longitudinal direction of the plunger from the center of the mounting portion of the plunger.

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