Orifice and operating cylinder

Abstract

To provide an orifice, with a relatively simple structure, that enables quickly releasing a clutch (with good responsiveness) while gradually engaging the clutch (reducing shock load torque).SOLUTION: An orifice 30 adjusts (restricts) an oil flow rate supplied to an operating cylinder 20 during releasing a clutch, and an oil flow rate discharged from the operating cylinder 20 during engaging the clutch. The orifice comprises: an annular body part 301 formed with an axial through-hole 302 axially passing through a center thereof; and a lip part 303 formed to protrude axially around the through-hole 302. The lip part 303 has elasticity and is formed such that its inner and outer diameters gradually decrease from a base end toward a tip end along the axial direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an orifice and an operating cylinder including the orifice.

Background Art

[0002] In a manual transmission, when shifting gears, the clutch pedal is depressed to disengage the clutch (i.e., disconnect the engine and the transmission to cut off the transmission of engine torque), the shift lever is operated to switch the gear position (gear), and after the shift (after shifting gears), the depression of the clutch pedal is released to re-engage the clutch (transmit the engine torque), and a series of operations are performed.

[0003] A hydraulic clutch includes, for example, a master cylinder that generates hydraulic pressure by depressing the clutch pedal (converts the depressing force (stepping force) into hydraulic pressure), and an operating cylinder that advances and retracts a push rod using the hydraulic pressure generated by the master cylinder to disengage and engage the clutch.

[0004] By the way, conventionally, in order to reduce the shock load torque that may occur when the clutch is suddenly engaged when the depression of the clutch pedal is released to engage the clutch, an operating cylinder provided with an orifice that restricts the flow rate of the discharged oil (an orifice is interposed in the oil passage) is known (see, for example, Patent Document 1).

[0005] More specifically, in the operating cylinder (release cylinder) of Patent Document 1, a valve body is integrally formed with the cylinder body, and a valve element with an orifice for restricting the flow path is formed inside the valve body. The valve element is movable forward and backward in the flow path by a first spring and a second spring made of a shape memory alloy that act according to the temperature of the liquid. When the temperature of the liquid is high, the first spring is hard and acts as a spring to push the valve element out into the flow path. When the temperature of the liquid is low, the first spring becomes soft, and the valve element is returned into the valve body 8 by the biasing force of the second spring, opening the flow path.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] According to the operating cylinder described in Patent Document 1, it is possible to cope with changes in the flow rate accompanying changes in the temperature (viscosity change) of the oil. However, in the operating cylinder (orifice) described in Patent Document 1, when the temperature of the oil is the same, the movement (response) becomes slow not only when the clutch is engaged but also when the clutch is released. That is, the movement becomes slow both when the clutch is released and when it is engaged. Therefore, there has been a desire to make the movement slow (while reducing the shock load torque) when engaging the clutch and quick (while enhancing the responsiveness) when releasing the clutch with a relatively simple structure (without causing complications, enlargement, high cost, etc.).

[0008] The present invention has been made to solve the above problems, and has a relatively simple structure, and while gently fastening the clutch (reducing the shock load torque), it is possible to quickly (responsive) release the clutch, and an orifice, and an operating cylinder including the orifice are provided.

Means for Solving the Problems

[0009] An orifice according to one aspect of the present invention is an orifice that adjusts the flow rate of the liquid supplied to the operating cylinder when the clutch is released and the flow rate of the liquid discharged from the operating cylinder when the clutch is fastened, and has a main body portion in which a through hole penetrating axially is formed at the center, and a lip portion formed to protrude axially around the through hole, and the lip portion has elasticity and is formed such that the inner diameter and the outer diameter become smaller as it approaches the tip from the base end along the axial direction.

[0010] According to the orifice according to one aspect of the present invention, it includes a main body portion in which a through hole penetrating axially is formed at the center, and a lip portion formed to protrude axially around the through hole, and the lip portion has elasticity and is formed such that the inner diameter and the outer diameter become smaller as it approaches the tip from the base end along the axial direction. Therefore, for example, when the liquid flows from the base end side to the tip side of the lip portion, the opening area of the lip portion increases due to the hydraulic pressure from the inside, the flow rate increases, and the clutch can be quickly released. On the other hand, for example, when the liquid flows from the tip side to the base end side of the lip portion, the opening area of the lip portion decreases due to the hydraulic pressure from the outside, the flow rate decreases, and the clutch can be gently fastened (reducing the shock load torque). In addition, the effect can be exhibited with only the orifice (a single part), that is, with a relatively simple configuration.

Effects of the Invention

[0011] According to the present invention, it is possible to gently engage the clutch (reduce the shock load torque) while having a relatively simple structure, and to quickly (responsive) release the clutch.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0013] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts will be denoted by the same reference numerals. Also, in each figure, the same elements will be denoted by the same reference numerals and redundant descriptions will be omitted.

[0014] First, with reference to FIG. 1, the configuration of an orifice 30 according to an embodiment and an operating cylinder 20 including the orifice 30 will be described. FIG. 1 is a cross-sectional view showing the configuration of the orifice 30 and the operating cylinder 20 including the orifice 30.

[0015] The operating cylinder 20 is communicated via an oil passage with, for example, a master cylinder (not shown) that generates hydraulic pressure (converts the stepping force (pedal force) into hydraulic pressure) by stepping on a clutch pedal, and uses the hydraulic pressure generated by the master cylinder to advance and retract a push rod 24 to release and engage a clutch (not shown). Note that known master cylinders and clutches can be used.

[0016] More specifically, a piston 23 is disposed within a cylinder body 21 of an operating cylinder 20 so as to be slidable in the axial direction. A cylinder chamber (hydraulic chamber) 22 is defined by the inner surface of the cylinder body 21 and the rear end surface of the piston 23. A push rod 24 is attached to the piston 23 so as to be able to advance and retreat in the axial direction together with the piston 23. The push rod 24 is configured to push a release fork and a diaphragm spring (not shown) at its tip. Further, a spring 25 that applies a biasing force in the pushing-out direction (the direction to release the clutch) to the piston 23 (push rod 24) is disposed between the rear end portion of the piston 23 and the rear end surface of the cylinder chamber (hydraulic chamber) 22.

[0017] Then, the piston 23 (push rod 24) is driven by a pressing force corresponding to the hydraulic pressure supplied to the cylinder chamber (hydraulic chamber) 22 (that is, a pressing force determined by the product of the hydraulic pressure and the pressure receiving area (the area of a surface perpendicular to the axis)). That is, when oil (hydraulic pressure) is supplied from the master cylinder to the operating cylinder 20 (cylinder chamber 22), the push rod 24 is pushed forward together with the piston 23 (the clutch is released). On the other hand, when oil (hydraulic pressure) is discharged from the operating cylinder 20 (cylinder chamber 22) to the master cylinder, the push rod 24 is pushed back together with the piston 23 (the clutch is engaged).

[0018] An orifice 30 that restricts the flow rate of oil is interposed between the master cylinder and the operating cylinder 20 (cylinder chamber 22) (oil passage). The orifice 30 adjusts (restricts) the flow rate (flow velocity) of the oil supplied to the operating cylinder 20 when the clutch is released and the flow rate (flow velocity) of the oil discharged from the operating cylinder 20 when the clutch is engaged. In this embodiment, the orifice 30 is incorporated into the operating cylinder 20.

[0019] Here, the orifice 30 has a relatively simple structure (without causing complication, enlargement, high cost, etc.), and while gently fastening the clutch (reducing the shock load torque), it has the function of quickly (responsive) releasing the clutch.

[0020] Therefore, the orifice 30 includes an annular (cylindrical) main body (body) 301 in which a through hole 302 penetrating axially in the center is formed, and a lip portion 303 formed (projected) to project axially around the periphery (outer periphery) of the through hole 302. The main body 301 is formed of, for example, a highly rigid rubber material or the like, and its outer periphery is press-fitted and fixed to the cylinder body 21.

[0021] The lip portion 303 has elasticity (flexibility), and is formed such that the inner diameter and the outer diameter become smaller (narrower) as it approaches the tip from the base end along the axial direction. The lip portion 303 is formed of, for example, a rubber material or the like having elasticity (flexibility).

[0022] In addition, the lip portion 303 is formed such that the reduction rate of the diameter gradually increases (the degree of diameter reduction increases) as it approaches the tip (gradually), so that the opening area (opening diameter) of the lip portion 303 easily increases and decreases according to the hydraulic pressure, and the cross section when cut along the axial direction draws an arc inward. That is, the outer shape of the lip portion 303 is formed in a substantially hemispherical (bowl shape). And the lip portion 303 is formed such that the wall thickness becomes thinner as it approaches the tip.

[0023] Here, when oil is supplied to the operating cylinder 20 when the clutch is released, the oil flows from the base end side to the tip side of the lip portion 303 (from the inside to the outside of the lip portion 303). On the other hand, when oil is discharged from the operating cylinder 20 when the clutch is fastened, the oil flows from the tip side to the base end side of the lip portion 303 (from the outside to the inside of the lip portion 303).

[0024] When the oil flows from the base end side to the tip end side of the lip portion 303, the opening area (opening diameter) of the lip portion 303 increases due to the hydraulic pressure from the inside, and the flow rate increases. On the other hand, when the oil flows from the tip end side to the base end side of the lip portion 303, the opening area (opening diameter) of the lip portion 303 decreases due to the hydraulic pressure from the outside, and the flow rate decreases.

[0025] Here, the opening area (opening diameter) of the orifice 30 is set so that the opening area (opening diameter) at the time of clutch engagement (when narrowed) is equal to the opening area (opening diameter) of the conventional orifice. Therefore, when the clutch is released, the opening area (opening diameter) becomes larger than that of the conventional orifice.

[0026] Furthermore, in order to regulate so that the lip portion 303 does not expand too much (to suppress the expansion of the lip portion 303 due to a hydraulic pressure load above a certain level), and also to prevent the lip portion 303 from remaining expanded, an annular garter spring 304 (biasing member described in the claims) that applies a biasing force in the diameter-reducing direction to the lip portion 303 is preferably attached around the base end portion (outer periphery) of the lip portion 303.

[0027] Next, the operation of the orifice 30 will be described with reference to FIGS. 2 to 4 together. FIG. 2 is a cross-sectional view and a front view showing the state of the orifice 30 at a steady state (when there is no oil flow). FIG. 3 is a cross-sectional view and a front view showing the state of the orifice 30 when the clutch is released. FIG. 4 is a cross-sectional view and a front view showing the state of the orifice 30 when the clutch is engaged.

[0028] As shown in FIG. 3, when the clutch is released (that is, when oil is supplied to the operating cylinder 20), when the oil flows from the base end side to the tip end side of the lip portion 303, the lip portion 303 is pushed and expanded from the inside by the hydraulic pressure from the inside, the opening area (opening diameter) of the lip portion 303 increases, and the flow rate of the oil increases. Therefore, the clutch is quickly (with good responsiveness) released.

[0029] On the one hand, as shown in FIG. 4, when the clutch is engaged (i.e., when oil is discharged from the operating cylinder 20), when the oil flows from the tip end side to the base end side of the lip portion 303, the lip portion 303 is pressed and narrowed by the hydraulic pressure from the outside, and the opening area (opening diameter) of the lip portion 303 is reduced, and the flow rate of the oil is decreased. Therefore, the clutch is gently engaged (i.e., the shock load torque is reduced).

[0030] As described in detail above, according to the present embodiment, when the clutch is released (when oil is supplied to the operating cylinder 20), when the oil flows from the base end side to the tip end side of the lip portion 303, due to the hydraulic pressure from the inside, the opening area of the lip portion 303 is increased and the flow rate is increased, so that the clutch can be quickly (responsive) released. On the other hand, when the clutch is engaged (when oil is discharged from the operating cylinder 20), when the oil flows from the tip end side to the base end side of the lip portion 303, due to the hydraulic pressure from the outside, the opening area of the lip portion 303 is reduced and the flow rate is decreased, so that the clutch can be gently engaged (the shock load torque is reduced).

[0031] Moreover, with only the orifice 30 (a single component), that is, the effect can be exhibited with a relatively simple configuration, and simplification of the structure, miniaturization of the operating cylinder 20, etc. can be achieved.

[0032] As a result, with a relatively simple structure (without causing complication, enlargement, high cost, etc.), the clutch can be gently engaged (the shock load torque is reduced), while the clutch can be quickly (responsive) released.

[0033] According to the present embodiment, the lip portion 303 is formed such that the diameter reduction rate becomes larger as it approaches the tip end (gradually), the cross section when cut along the axial direction forms an arc on the inside, and the wall thickness becomes thinner as it approaches the tip end. Therefore, according to the hydraulic pressure, the opening area (opening diameter) of the lip portion 303 is easily increased and decreased.

[0034] According to this embodiment, an annular garter spring (garter spring) 304 that applies a biasing force in the diameter-reducing direction to the lip portion 303 is attached around the base end portion of the lip portion 303. Therefore, it is possible to regulate the lip portion 303 so that it does not expand too much. Also, it is possible to prevent the lip portion 303 from remaining expanded.

[0035] As described above, the embodiments of the present invention have been described, but the present invention is not limited to the above embodiments and various modifications are possible. For example, in the above embodiment, the lip portion 303 is formed such that the cross-section cut along the axial direction draws an arc inward, that is, in a substantially hemispherical (bowl-shaped) form. However, the lip portion 303 may be formed, for example, such that the cross-section cut along the axial direction linearly narrows (in a substantially frustum-of-a-cone shape), or may be formed such that the cross-section cut along the axial direction draws an arc outward.

[0036] Also, in the above embodiment, the orifice 30 is incorporated (integrated) into the operating cylinder 20. However, depending on requirements such as layout, for example, the orifice 30 and the operating cylinder 20 may be separated.

Explanation of Reference Numerals

[0037] 20 Operating cylinder 21 Cylinder body 22 Cylinder chamber (hydraulic chamber) 23 Piston 24 Push rod 25 Spring 30 Orifice 301 Main body portion 302 Through hole 303 Lip portion 304 Garter spring (biasing member)

Claims

1. An orifice that adjusts the flow rate of the liquid supplied to the operating cylinder when the clutch is released and the flow rate of the liquid discharged from the operating cylinder when the clutch is engaged, comprising a main body portion having a through hole axially penetrating therethrough at the center, and a lip portion formed to protrude axially around the through hole, wherein the lip portion has elasticity and is formed such that the inner diameter and the outer diameter become smaller from the base end portion to the tip end portion along the axial direction. The orifice is characterized by this.

2. When the liquid is supplied to the operating cylinder, the liquid flows from the base end portion side to the tip end portion side of the lip portion, When the liquid is discharged from the operating cylinder, the liquid flows from the tip end portion side to the base end portion side of the lip portion. The orifice according to claim 1 is characterized by this.

3. The lip portion is formed such that the diameter reduction rate increases as it approaches the tip end portion, the cross section when cut along the axial direction draws an arc inward, and the wall thickness becomes thinner as it approaches the tip end portion. The orifice according to claim 2 is characterized by this.

4. The orifice according to claim 3, further comprising an annular biasing member attached around the base end portion of the lip portion and applying a biasing force to the lip portion in the diameter reduction direction.

5. An operating cylinder that advances and retracts a push rod using hydraulic pressure to engage and disengage a clutch, The operating cylinder is characterized by comprising the orifice according to claim 1.

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