JP3450931B2 - Check valve for hydraulic tensioner - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a check valve, and more particularly, to an opening formed in a housing of a hydraulic tensioner having a housing and an extendable plunger. The present invention relates to a check valve externally attached to a part. 2. Description of the Related Art Hydraulic tensioners have conventionally been used to suppress rattling of chains and belts due to fluctuations in engine torque and to reduce noise, vibration, guide wear and the like. The hydraulic tensioner generally includes a housing, a plunger supported by the housing so as to be extendable and retractable, and a distal end of the plunger abutting on a tensioner arm, and a spring for biasing the plunger in a protruding direction. Has an oil chamber in which an external oil pressure acts. [0003] The housing is generally provided with an opening for introducing an external oil pressure. The opening allows the flow of the hydraulic oil toward the oil chamber and the flow in the opposite direction. A check valve for regulating the pressure is provided from the outside. A conventional hydraulic tensioner check valve is, for example, as shown in FIG.
A body 103 attached to an opening 102 formed in a housing 101, a ball 104 housed in the body 103, and a spring 105 one end of which is pressed against the ball 104. The ball 104 is constantly urged toward the seat surface 106 side. The other end of the spring 105 is connected to the body 10
3 is pressed against the bottom wall 107, that is, the bottom wall 1
07 functions as a retainer for the spring 105. A small hole 108 communicating with the oil chamber of the hydraulic tensioner 100 is formed in the bottom wall 107. [0005] In the hydraulic tensioner having such a check valve 100, when the pressure in the oil chamber decreases as a result of the chain or belt becoming loose, the ball 1
04 is separated from the seat surface 106, hydraulic oil is introduced from the outside into the body 103, and the introduced hydraulic oil
8 to the oil chamber. Conversely, if the pressure in the oil chamber increases as a result of the tension applied to the chain or the belt, the pressure is introduced into the body 103 through the small hole 108, thereby causing the ball 104 to move to the seat surface 106.
, So that backflow of the hydraulic oil is prevented. In the above-described conventional check valve 100, hydraulic oil is introduced into the oil chamber through a small hole 108 formed in the bottom wall 107 of the body 103. Therefore, the flow resistance is large, and the hydraulic oil may not be smoothly introduced into the oil chamber. In such a case, the responsiveness of the hydraulic tensioner is reduced. Further, since the body 103 is press-fitted into the opening 102 formed in the housing 101, the opening 10
The inner peripheral surface 2 and the outer peripheral surface of the body 103 need to be processed with high accuracy, and the processing cost increases. further,
Due to the press-fitting, when the pressure in the oil chamber becomes high, the check valve 100 may fall out of the opening 102. SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and it is possible to smoothly introduce hydraulic oil into an oil chamber of a hydraulic tensioner and prevent a check valve from falling off. It is another object of the present invention to provide a hydraulic tensioner check valve that can reduce the processing cost of the entire hydraulic tensioner and can be easily assembled to the hydraulic tensioner. [0008] A check valve for a hydraulic tensioner according to the present invention is a hydraulic tensioner having a housing and a plunger inserted into the housing so as to be extendable and retractable. a hydraulic tensioner check valve mounted externally to the opening which is, also with the external thread portion to be screwed into a female screw portion formed in the opening portion is formed on the outer periphery, the check ball A substantially cylindrical body having a valve chamber accommodated therein, a spring for urging the check ball toward the seat surface side in the valve chamber, and a plurality of legs extending radially in a radial direction ; The tip of the leg is
Along the inner peripheral surface of the valve chamber in the same plane as the extension direction
A retainer supporting the spring, which is bent in the circumferential direction and is elastically held by being pressed against the inner circumferential surface of the opening end of the valve chamber from the circumferential direction , and a valve chamber side of the body. And an engaging portion provided on the opposite side and capable of engaging with a tool for attaching the body to the housing. According to the present invention, since the retainer has the legs of a plurality of limbs, the openings between the adjacent legs can be used as a flow path for the hydraulic oil. As a result, a large opening area is secured as compared with a conventional small hole, and as a result,
Hydraulic oil can be smoothly introduced into the oil chamber. Also, since the external thread portion formed on the outer peripheral portion of the body is screwed into the threaded portion formed in the housing opening portion, the body is attached to the housing opening portion. Processing accuracy is not required as much as press fitting, and processing cost can be reduced. In addition, since both are engaged by screwing the screws, it is possible to prevent the check valve from easily falling off. Further, for mounting by screwing the screws,
Assembly to the hydraulic tensioner can be performed easily.
Moreover, in this case, since the engaging portion with which the mounting tool is engaged is provided, the check valve can be more easily assembled by using the mounting tool. An embodiment of the present invention will be described below with reference to the accompanying drawings. 1 and 2 are views for explaining a check valve for a hydraulic tensioner according to one embodiment of the present invention. 1 is a front sectional view of a hydraulic tensioner employing the present check valve, FIG. 2 is a view showing the present check valve, (a) is a plan view, (b) is a front sectional view, and (c) is a bottom face. FIG. In FIG. 1, a hydraulic tensioner 1 has a housing 2 having a hole 2a having an opening at one end, and a contact portion which is inserted into the hole 2a so as to be extendable and retractable and which contacts a tensioner arm (not shown). The plunger 3 has a coil spring 4 for urging the plunger 3 in a protruding direction. The rear end of the coil spring 4
It is in pressure contact with the support member 5 press-fitted into the hole opening of the housing 2. In the hole 2a of the housing 2, there is formed an oil chamber 6 defined by the inner wall surface of the hole 2a, the outer peripheral surface of the plunger 3, and the end surface of the support member 5. The oil chamber 6 is supplied with a hydraulic pressure from an external hydraulic circuit (not shown) including an oil pump via a check valve 10. The check valve 10 is attached to an opening 8 formed in the housing 2, and an oil passage 9 is formed between the opening 8 and the oil chamber 6. The check valve 10 has a substantially cylindrical body 11 as shown in FIG.
Is formed with an external thread portion 11a on the outer periphery thereof. The external thread 11a is formed on the inner periphery of the opening 8 (FIG. 1), and is screwed to the thread. A cross-shaped groove 12 is formed in an upper portion of the body 11 so that a tip of a plus (or minus) driver as a mounting tool can be engaged with the groove. Note that, instead of the groove 12, a hexagonal hole with which a hexagonal wrench is engaged may be formed, or a hexagonal head with which a spanner may be engaged may be formed. A valve chamber 13 is formed in the body 11, and a ball (check ball) 1 is provided in the valve chamber 13.
4 are accommodated. In the valve chamber 13, a ball 14 is provided.
A spring 16 for urging the sheet toward the seat surface 15 is provided. A spring 16 is provided at the open end of the valve chamber 13.
Is provided. Retainer 1
7 is a plurality of limbs extending radially in the radial direction (here, 4 limbs).
), And an opening 19 is formed between each adjacent leg 18. Of each leg 18
The tip portion 18a is in the same plane as the extending direction of each leg portion 18.
At the inner peripheral surface 20 of the open end of the valve chamber 13
It is bent in the direction. In addition, when the retainer is mounted, the distal end portion 18a of each leg portion 18 is deformed inward (center side), and is elastically held by being pressed against the inner peripheral surface 20 of the valve chamber opening end from the circumferential direction. I have. Since the retainer 17 is elastically held in the circumferential direction as described above, the retainer 17 is not deformed in the plate thickness direction like a disc spring, and the retainer 17 can be attached to the plate by using the plate. It is sufficient if a dimension corresponding to the thickness is secured. Thus, the length of the check valve 10 in the axial direction (the vertical direction in FIG. 2B) can be minimized, and the entire check valve can be reduced in size. Next, the operation and effect of this embodiment will be described. If the chain or belt on which the pressing force of the hydraulic tensioner 1 by the plunger 3 is acting becomes loose,
As a result of the plunger 3 projecting slightly by the spring force of the coil spring 4, the pressure in the oil chamber 2a decreases. Then, in the check valve 10, the ball 14 is seated on the seat surface 1.
5 (see the dashed line in FIG. 2 (b)), hydraulic fluid is introduced into the body 11 from outside. The introduced hydraulic oil is
It passes through each opening 19 formed between the legs 18 of the retainer 17, and is further introduced into the oil chamber 2 a via the oil passage 9 of the housing 2. Conversely, when a tension is applied to the chain or the belt, the plunger 3 tries to retreat against the spring force of the coil spring 4, so that the pressure in the oil chamber 2a increases. Then, this pressure is introduced into the body 11 through each opening 19 of the retainer 17. As a result, the ball 14 comes into contact with the seat surface 15 and backflow of the hydraulic oil is prevented. As described above, according to the present embodiment, the retainer 1
Since each of the legs 7 has a plurality of legs 18, each opening 19 between the adjacent legs 18 can be used as a flow path for hydraulic oil. Thereby, a large flow passage opening area can be secured, and as a result, hydraulic oil can be smoothly introduced into the oil chamber 2a, and the responsiveness of the hydraulic tensioner 1 can be improved. The mounting to the hydraulic tensioner 1 is performed by screwing a male thread portion 11a formed on the outer peripheral portion of the body 11 to the thread portion formed in the housing opening portion 8, so that the machining is so expensive. Accuracy is not required, and processing costs can be reduced. In addition, since the two are engaged by the screwing of the screws, it is possible to prevent the check valve 10 from easily falling out of the opening 8. Further, for mounting by screwing,
Assembly to the hydraulic tensioner 1 can be easily performed. Moreover, in this case, the groove 12 with which the driver engages is used.
Is formed, the use of a driver makes it easier to assemble the check valve 10. In the above-described embodiment, an example is shown in which the present invention is applied to a hydraulic tensioner employed in a timing system for an automobile engine. However, the invention is employed in a timing system for a motorcycle engine. The same can be applied to a hydraulic tensioner. FIG. 3 shows an example of such a hydraulic tensioner. In FIG. 3, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. The hydraulic tensioner 1 'is different from the hydraulic tensioner in that the check valve 10 is disposed at the end of the housing 2. With this configuration, it is possible to easily connect to the oil passage 40 from the outside of the engine. As described above, according to the check valve for a hydraulic tensioner according to the present invention, since the retainer has the legs of a plurality of limbs, the opening between the adjacent legs is formed by the hydraulic oil. Thus, there is an effect that a large opening area can be secured and the hydraulic oil can be smoothly introduced into the oil chamber. Also, since the external thread portion of the body is screwed into the female thread portion of the housing opening to assemble to the hydraulic tensioner, the processing cost can be reduced and the check valve easily falls off from the hydraulic tensioner. Can be prevented. Further, since the engagement portion with which the mounting tool is engaged is provided, the check valve can be more easily assembled.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front sectional view of a hydraulic tensioner employing a check valve according to an embodiment of the present invention. FIG. 2 is an enlarged view of the check valve, and FIG.
Is a plan view, (b) is a front sectional view, and (c) is a bottom view. FIG. 3 is a diagram showing another application example of the present invention. FIG. 4 is a front sectional view of a conventional check valve,
The figure corresponding to (b) of FIG. [Description of Signs] 1 Hydraulic tensioner 2 Housing 3 Plunger 8 Opening portion 10 Check valve 11 Body 11a Male thread portion 12 Groove (tool engaging portion) 13 Valve chamber 14 Ball (check ball) 15 Seat surface 16 Spring 17 Retainer 18 Leg 18a tip

Claims (1)

(57) [Claim 1] In a hydraulic tensioner having a housing and a plunger inserted into the housing so as to be extendable and retractable, the hydraulic tensioner is externally attached to an opening formed in the housing. A check valve for a hydraulic tensioner, wherein a male screw portion formed in the opening portion and screwed to a screw portion is formed on an outer periphery, and has a substantially cylindrical shape having a valve chamber for accommodating a check ball therein. A body, a spring for urging the check ball toward the seat surface side in the valve chamber, and a plurality of legs extending radially in a radial direction, the tip of each leg extending from the leg. Front in the same plane as the installation direction
The spring, which is bent in the circumferential direction along the inner peripheral surface of the valve chamber and is elastically held by being pressed against the inner peripheral surface of the opening end of the valve chamber from the circumferential direction, is elastically supported. A check valve for a hydraulic tensioner, comprising: a retainer which is provided on the opposite side to the valve chamber side of the body, and an engaging portion which can be engaged with a tool for attaching the body to the housing.