JPS644587Y2 - - Google Patents

Description

[Detailed Description of the Invention] (1) Technical Field The present invention relates to a hub lock that can prevent a decrease in performance and durability and malfunction due to the collapse of the first brake member.

(2) Background technology Here, hub lock refers to a freewheel hub clutch, and hub lock refers to a freewheel hub clutch in a four-wheel drive vehicle that can switch between two-wheel and four-wheel drive modes at any time. This is a device for separating or joining the shaft as necessary. The hub lock prevents the front wheel drive shaft from spinning when the vehicle is running on two wheels, thereby solving problems in terms of noise and fuel consumption.

As a freewheel hub clutch (hereinafter referred to as a hub lock) that was previously proposed by the present applicant, there is one shown in FIGS. 1A and 1B to 3A and 3B, for example. A drive gear 2 that is coupled and has a spline portion on its outer periphery and a pawl 2a that directly drives the first brake member 7.
, a slide gear 3 that is spline-coupled to the drive gear 2 at the inner circumference and has a gear section on the outer circumference and is movable in the axial direction; The housing 4 is fixed to the wheel hub 16 through bolts 15, and the slide gear 3 is spline connected to the slide gear 3.
A cam 5 that is movable over a predetermined distance in the axial direction of
, a retainer 6 which has a V-shaped groove-shaped cam portion (second cam portion) 6a that engages with the cam 5 and is rotatably disposed outside the drive gear 2;
A cam portion (first cam portion) 7a that engages with the claw 2a of
and a cam portion (second cam portion) 7b that engages with a V-shaped protruding cam portion (first cam portion) 6b of the retainer 6.
It is directly driven by the drive gear 2 via the pawl 2a that engages with the second cam portion 7a when the engagement between the cam 5 and the retainer 6 is released, and has a friction sliding surface. a first brake member 7 that is freely movable in the axial direction; an elastic member 8 that biases the first brake member slightly to the left; and a friction sliding surface that makes frictional contact with the friction sliding surface of the first brake member 7. a second brake member 11 that has a predetermined spring force and is disposed coaxially on the outside of the slide gear 3 in the radial direction and has one end connected to the retainer 6; A first coil spring 13 is seated and its other end is seated on the cam 5 via a spring holder 12 to press the cam 5 to the left (inward) in the axial direction. installed first coil spring 1
The second coil spring 14 has a spring force smaller than 3 and presses the slide gear 3 to the right in the axial direction.

In the above configuration, Fig. 1A, Fig. 2A,
When you want to switch from the two-wheel drive (hereinafter referred to as "2WD") shown in B to the four-wheel drive (hereinafter referred to as "4WD") shown in FIG. Operate the lever to change from 2WD to 4WD
When the switch is switched to , the drive shaft 1 starts rotating. Then, the drive gear 2 spline-coupled to the drive shaft 1 rotates, and the slide gear 3 spline-coupled to the drive gear 2 also rotates together with the cam 5. Here, the cam 5 has a protrusion and is connected to the second cam portion 6a of the retainer 6.
Because it is fitted into the retainer 6, rotational force acts on the retainer 6,
Due to this rotational force, the V of the left side of the retainer 6 in the axial direction is
A rotational force also acts on the first brake member 7 via the first cam portion 6b shaped like a protrusion and the V-shaped groove shaped cam portion 7b of the first brake member 7 that engages with the first cam portion 6b. However, since the friction sliding surface of the first brake member 7 is in light contact with the friction sliding surface of the second brake member 11 rotationally fixed by the spindle 9 due to the elastic body 8, the first cam portion 6b and the second cam portion 7b, the first brake member 7
is pressed to the left in the axial direction, and the second brake member 1
Press 1. As a result, the braking force generated by the frictional contact between the first brake member 7 and the second brake member 11 brakes the first brake member 7 and the retainer 6 to suppress rotation, and there is a gap between the cam 5 and the retainer 6. The relative rotation generates a thrust force in the axial direction, compressing the cam 5 and the first coil spring 13 and moving the cam 5 to the right in the axial direction to the positions shown in FIG. As a result, the slide gear 3 moves to the right in the axial direction via the second coil spring 14 and engages with the gear of the housing 4, thereby coupling the drive shaft 1 and the housing 4 to obtain 4WD. At this time, as shown in FIG.
The force that rotates disappears, and the drive shaft 1 and the first brake member 7 rotate relative to each other, and the pawl 2a of the drive gear 2 engages the first cam portion 7a of the first brake member 7 ( (See Figure 3 A),
The first brake member 7 is directly driven from the drive shaft 1 via the pawl 2a and the first cam portion 7a,
The thrust force generated at the engagement cam portion between the retainer 6 and the first brake member 7 is released.

Further, when a relative rotational force is generated between the first brake member 7 and the drive shaft 1, the elastic member 8 biases the first brake member 7 inward in the axial direction. A slight preliminary braking force is generated between the brake member 11 and the axially inward thrust force generated at the cam portion between the first brake member 7 and the retainer 6 is increased based on the preliminary braking force. and based on the increased thrust force, the first brake member 7 and the second brake member 1
Sufficient braking force can be generated between 1 and 1.

Also, when changing from 4WD to 2WD, when the shift lever is switched from 4WD to 2WD and the car is moved slightly in the opposite direction to the direction in which it has been traveling, the cam portion 7a of the first brake member 7 and the drive gear 2 Since the pawl 2a is separated and the input to the first brake member 7 is only from the V-shaped grooved cam portion 7b as described above, the rotation of the first and second brake members 7 and 11 is suppressed. As the vehicle moves, the axle rotates, and the housing 4 rotates the slide gear 3 and drive shaft 1, but the retainer 6 is fixed by the first and second brake members 7 and 11, so the retainer 6 is relative to the cam 5. The first
Due to the action of the coil spring 13, the V-shaped protrusion of the cam 5 falls into the cam portion 6a of the retainer 6. Therefore, the slide gear 3 moves leftward to the positions shown in FIG. 1A and FIG. 2B. As a result, housing 4
The coupling with the slide gear 3 is released, the rotation of the drive shaft 1 is stopped, and 2WD is obtained. However, in the conventional hub lock, the axial storage space for the elastic member 8 is narrow, so the number of turns is extremely small, and as a result of the small number of turns, the pressing force of the elastic member 8 becomes uneven. Since the elastic member 8 is configured to constantly contact the first brake member 7 and always bias it inward in the axial direction, the load point on the first brake member 7 is biased due to the small number of windings. state (the state in which the first brake member 7 has fallen down), the second brake member 1
1 (see Figure 4 A and B).
In particular, since the first brake member 7 has a pair of cam portions 7a at symmetrical positions on the inner circumferential surface, it often falls about a straight line (fall axis) connecting the pair of cams 7a. In this way, if the first brake member 7 falls beyond the limit of its self-aligning ability, the frictional sliding surfaces of both brake members 7 and 11 will not be able to properly contact each other. Local wear occurs on the sliding portion, which prevents the generation of appropriate braking force, leading to malfunction and reduced performance and durability.

(3) Purpose and effect of the invention The present invention has been made in view of the above, and the first brake member falls down due to uneven pressing force of the elastic member, thereby preventing the proper relationship between the first brake member and the second brake member. In order to prevent the generation of braking force from being obstructed, an elastic member locking step consisting of a groove, protrusion, etc. is formed on the cam portion of the retainer that protrudes inward in the axial direction, and the locking step is formed by the locking step. Provided is a hub lock which limits the amount of expansion of the elastic member in the axial direction by locking the axially inner end of the elastic member, thereby correcting the inclination of the first brake member. It is something to do.

(4) Embodiment The hub lock of the present invention will be explained below (see also FIG. 1 A and B to FIG. 3 A and B).

Figures 5A and 7A to 7B show an embodiment of the hub lock of the present invention, and the same parts as in Figures 1A and 2B to 3A and B are designated by the same reference numerals, and duplicate explanations will be omitted. Although omitted, the first cam portion 6b of the retainer 6
A groove (elastic member locking step) 17 is formed on the outer peripheral surface of the groove 17, and one end of the elastic member 8 is locked to the axially inner (first brake side) edge of the groove 17. This is different from Figure 1 A and B to Figure 3 A and B. Note that instead of forming the groove 17, a protruding locking step may be formed to protrude, and one end of the elastic member may be locked by the locking step.

In the above configuration, when no axially inward thrust force is generated at the engagement portion between the first cam portion 6b of the retainer and the second cam portion 7b of the first brake member, for example, during 2WD driving and During 4WD driving, the first brake member 7 is located axially outward as shown in Fig. 5 A and B, and when the axially inward thrust force is generated, For example, when switching from 2WD to 4WD, the first brake member 7 is pressed against the second brake member 11 by the first cam portion 6b of the retainer, as shown in FIGS. 6A and 6B. When the pressing force of the elastic member 8 is uniform, the first brake member 7 properly contacts the friction sliding surface of the second brake member 11 without collapsing. In addition, as shown in FIG. 7, the first brake member may fall down when switching from 2WD to 4WD due to uneven pressing force of the elastic member 8 on the engagement surface between the elastic member 8 and the first brake member 7. Even if it is pressed inward in the axial direction in this state, the posture is corrected before it is completely engaged with the second brake member 11, so there is no problem in generating an appropriate braking force.

To explain this in detail, for example, the first brake member 7
When pressed inward in the axial direction by the cam part 6b in a state where the brake member is tilted (tilted outward in the axial direction) as shown by the solid line in FIG. The lower part of the elastic member 8 corresponding to the part (the part protruding inward in the axial direction) is already in the expanded state and the elastic force is small, so the lower part of the first brake member 7 is strongly pressed. In contrast, the upper part of the elastic member 8 corresponding to the upper part of the first brake member 7 (the part protruding outward in the axial direction) is in a compressed state and the elastic force increases. Therefore, the upper part of the first brake member 7 is strongly pressed inward in the axial direction. The lower side of the elastic member 8 not only has a small elastic force, but also moves the lower side of the first brake member 7 axially inward beyond the axially inner edge (or locking projection) of the groove 17. Since no pressure is applied to the first brake member 7, the amount of axial inward displacement of the lower side of the first brake member 7 is zero or slight. On the other hand, since the upper part of the elastic member 8 has a large elastic force, the upper part of the first brake member 7 is pressed while the lower part of the first brake member 7 is in a stopped state. , and correct its posture by displacing it to the upright position shown by the dotted line. Therefore, at the time of engagement with the second brake member 11, the first brake member 7 can always maintain an appropriate posture, and therefore, an appropriate braking force can be obtained. In addition, an elastic member 8 is provided at a position axially inner than the groove 17 (or the locking step).
Since the pressing force is not applied, the first brake member 7 will not be pressed by the elastic member 8 and fall off from the drive gear 2 when the first brake member 7 is assembled.

Next, the relationship between the amount of inclination (the amount of axial displacement) δ of the first brake member 7 and the pressing force P of the elastic member 8 will be explained based on FIG. 8A. The X-axis represents the amount of axial displacement based on the inclination of the first brake member 7, and the Y-axis represents the force of the elastic member 8 pressing the first brake member 7 against the second brake member 11. Straight line Z
indicates the axial position of the locking step portion 17, and at the same time indicates the limit of the amount of expansion of the elastic member 8 in the axial direction.
A1 and A2 each indicate the point of action of the elastic member 8,
A1 represents the point of action at the outermost position in the axial direction, and A2 represents the point of action at the innermost position in the axial direction. The pressing force acting on A1 is P1, the pressing force acting on A2 is P2, and the first
If the correction force acting on the brake member is P0, then
P0=P1−P2. When A2 is inward (to the left) of the locking step position Z in the state shown in Figure 8, P2 is zero, so P0 = P1, and the pressurizing force acting on A1 becomes a strong correction force, causing the 1 Correct the brake member 7 to an upright state. In the conventional example, the pressurizing force P2 changes linearly from the origin 0 of X and Y, whereas in the present invention, the pressurizing force P2 is zero from the origin 0 to the step position Z. As soon as A1 reaches position Z of the stepped part, it becomes a constant value, and then A1
As it moves outward (to the right), it changes along the same line as in the conventional example.

Figure 8 B shows the correction force in the case of Figure 8 A.
The graph shows the change in P0, and the solid line shows the change in the correction force in the present invention, and the dotted line shows the change in the correction force in the conventional example.

(5) Effects of the invention As explained above, according to the hub lock of the invention, an elastic member locking step consisting of a groove, protrusion, etc. is formed on the cam portion of the retainer that protrudes inward in the axial direction. By locking the axially inner end of the elastic member with the locking step, the amount of axially inward expansion of the elastic member is limited, thereby correcting the inclination of the first brake member. As a result, it is possible to prevent the first brake member from collapsing due to uneven pressing force of the elastic member, thereby preventing generation of appropriate braking force between the first brake member and the second brake member.

[Brief explanation of the drawing]

Figures 1A and 2B are cross-sectional views of a conventional hub lock during two-wheel drive and four-wheel drive, and Figures 2A and 2B are cross-sectional views of Figure 1A and explanatory diagrams of the engaged state of each member. , FIGS. 3A and 3B are cross-sectional views of FIG. An explanatory diagram when the brake member falls down,
Figure 5 A and B and Figure 6 A and B show the hub of the present invention.
One embodiment of the lock is shown in Figures 5A and 5B, which are explanatory diagrams and partially enlarged explanatory diagrams of the engaged state of each member during two-wheel drive, and Figures 6A and 6B are illustrations of the engagement state of each member during four-wheel drive. An explanatory diagram and a partially enlarged explanatory diagram of the engaged state, FIG. 7 is an explanatory diagram of the state in which the posture of the first brake member is corrected, and FIG. FIG. 8B is a graph showing the relationship between the amount of inclination and the correction force. Explanation of symbols, 1...Driveshaft, 2...
Drive gear, 2a... pawl, 3... slide gear, 4... housing, 5... cam, 6... retainer, 6a, 6b... cam portion, 6c... retainer end surface, 6d... locking recess, 6e...Locking convex portion, 7
...First brake member, 7a, 7b...Cam part,
8... Elastic member, 9... Fixed spindle, 10
... Nut, 11 ... Second brake member, 13,
14... Spring, 15... Bolt, 16... Wheel hub, 17... Elastic member locking portion.

Claims (1)

[Claims for Utility Model Registration] A housing that is fixed to a wheel hub with bolts and has a gear portion on its inner circumference, and a spring that biases the housing in the direction of disengaging the gear portion of the housing when the drive shaft is driven. A slide gear that engages with the gear portion of the housing against a mechanism and a first cam portion of the retainer generates an axially inward thrust force between the first cam portion and the first cam portion of the retainer. a first brake member having a cam portion that rotates and a friction sliding portion that generates a braking force based on the thrust force; a second brake member rotationally fixed to the slide gear; a cam spline-coupled at the outer periphery of the slide gear and disposed to be movable in the axial direction against the spring mechanism; and a second brake member engaged with the cam. a retainer having a first cam portion that engages with a second cam portion and a cam portion of the first brake member; a retainer disposed between the retainer and the first brake member; In the hub lock having an elastic member that presses the brake member against the second brake member, an elastic member locking step portion is formed on the outer periphery of the first cam portion of the retainer, and the elastic member locks the elastic member. A hub lock, characterized in that the hub lock is stretched between a stop portion and one end surface of the retainer.