JP2008163814A - Vacuum pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a load applied to a part in a vacuum pump when starting a rotor, with a simple constitution. <P>SOLUTION: In this vacuum pump 10, a rotational sliding part 18a and an intermediate driving member 17 are interposed between a driving shaft and a rotor, and transmit driving force applied from a camshaft 12 to the rotor when torque smaller than a predetermined value is applied to the intermediate driving member 17, and transmit the torque smaller than the predetermined value to a rotor body part 18e when torque larger than the predetermined value is applied to the intermediate driving member 17. At this time, the rotor body part 18e and the intermediate driving member 17 change the predetermined value so as to make it a value larger in rotation of the rotor body part 18e than when starting the rotor body part 18e. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vacuum pump, and more particularly to a vacuum pump that generates a negative pressure by rotating a rotor with a driving force applied from a drive shaft.

Vehicles are provided with various engine accessories that operate by the driving force of the engine. In order to prevent an excessive load torque from being applied to a compressor which is such an engine accessory, for example, a compressor pulley device including a torque limiter mechanism has been proposed (see, for example, Patent Document 1). Further, in order to suppress the engine load, for example, when the rotational speed of the rotary shaft is equal to or greater than a predetermined value, the connection member and the rotary shaft are disconnected, and the rotational force from the rotary shaft to the rotor is cut off. A machine has been proposed (see, for example, Patent Document 2). Further, for example, a rotary compressor that combines a rotary compressor and a pressure multi-plate clutch and gradually connects the pressure multi-plate clutch to reduce a connection shock at the start of rotation of the compressor has been proposed (for example, Patent Document 3). reference).
JP 2004-218669 A JP 2003-278676 A JP-A-62-7992

  2. Description of the Related Art A vacuum booster that generates a negative pressure with a vacuum pump is known as a booster that assists the driver when the brake pedal is depressed by a driver. In such a vacuum booster, a rotating member such as a rotor is rotated, and negative pressure is generated by expanding and compressing air in an empty chamber by a vane or the like. In such a vacuum booster, in order to maintain good performance, when a rotating member such as a rotor is rotating, lubricating oil is supplied to the rotating sliding portion. For this reason, if the engine is started at a very low temperature, the vacuum pump is operated in a state where the viscosity of the lubricating oil is high, and a large load is applied to the rotor, vane, and even the camshaft in the vacuum pump. Will give. For this reason, the development of a new technique that reduces the load applied to each of these components at the time of starting the rotor with a simple configuration is required.

  The present invention has been made in view of these problems, and an object thereof is to reduce the load applied to the components in the vacuum pump at the time of starting the rotor with a simple configuration.

  In order to solve the above-described problems, a vacuum pump according to an aspect of the present invention is a vacuum pump that generates a negative pressure by rotating a rotor with a driving force applied from a driving shaft. A load reducing means for transmitting a torque applied when a torque smaller than a predetermined value is applied to the rotor, and transmitting a torque smaller than a predetermined value to the rotor when a torque larger than the predetermined value is applied. Is provided. The load reducing means changes the predetermined value so that the value during rotation of the rotor is larger than that at the time of starting the rotor.

  According to this aspect, when a torque larger than a predetermined value is applied, the load applied to components in the vacuum pump at the time of starting the rotor is reduced by a simple configuration in which torque smaller than the predetermined value is transmitted to the rotor. Can be made. Further, when a certain amount of time has passed since the engine started, the lubricating oil is also warmed and the viscosity is lowered. At this time, it is required to reliably rotate the rotor to generate negative pressure. According to this aspect, since the engagement between the rotor and the drive shaft can be made firm while the rotor is rotating, the drive force from the drive shaft can be reliably transmitted to the rotor.

  The load reducing means includes a first transmission member having an insertion hole coaxial with the rotor, rotating with the rotor, a second transmission member inserted through the insertion hole, and rotated by a driving force applied from a drive shaft, You may have a latching member which latches relative rotation of a transmission member and a 2nd transmission member, and a biasing means which gives biasing force to a latching member. The first transmission member may have a recess that is recessed radially outwardly on the inner surface of the insertion hole. The second transmission member may have an accommodation hole that opens to the outer surface of the insertion portion that is inserted through the first transmission member and accommodates the locking member. The biasing means applies a biasing force to the locking member so as to press the locking member accommodated in the receiving hole toward the recess, and the locking member is received in the receiving hole and pressed into the recess. When the relative rotation between the first transmission member and the second transmission member is locked and a torque larger than a predetermined value is applied, the first transmission member and the second transmission member are disengaged from the recess. The rotation lock may be released.

  According to this aspect, first, when a torque larger than a predetermined value is applied at the time of starting the rotor, the locking member is released from the recess, and the relative rotation of the first transmission member and the second transmission member is locked. By releasing, it is possible to avoid applying an excessive load to the components in the vacuum pump. In addition, since the locking member is strongly pressed against the concave portion by centrifugal force during the rotation of the rotor, the relative relationship between the first transmission member and the second transmission member is not increased during the rotation of the rotor unless a high torque is applied compared to when the rotor is started. Rotation lock is not released. For this reason, it is possible to reliably transmit the driving force from the drive shaft to the rotor while the rotor is rotating.

  Another aspect of the present invention is also a vacuum pump. This vacuum pump is a vacuum pump that generates a negative pressure by rotating a rotor with a driving force applied from a drive shaft, a first transmission member having a first pressing surface that rotates together with the rotor, and coaxial with the rotor. A second transmission member that has a rotatable second pressing surface and is rotated by a driving force applied from the drive shaft, and the first pressing surface and the second pressing surface are pressed against each other. Biasing means for biasing one of the first transmission member and the second transmission member toward the other. The first transmission member and the second transmission member are driven by locking relative rotation by a frictional force between the first pressing surface and the second pressing surface when a torque smaller than a predetermined value is applied. A driving force applied from the shaft is transmitted to the rotor, and when a torque larger than a predetermined value is applied, the driving force is relatively rotated to transmit a torque smaller than the predetermined value to the rotor. According to this aspect, the load applied to the components in the vacuum pump at the time of starting the rotor can be reduced by a simple configuration in which the first pressing surface and the second pressing surface are pressed.

  ADVANTAGE OF THE INVENTION According to this invention, the load given to the components in a vacuum pump at the time of rotor starting can be reduced with a simple structure.

  Hereinafter, embodiments of the present invention (hereinafter referred to as “embodiments”) will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a cross-sectional view of a vacuum pump 10 according to the first embodiment. The vacuum pump 10 includes a cam shaft 12, a coupling 14, a central support member 16, an intermediate drive member 17, a rotor 18, an oil supply pipe 40, a housing 24, a cover 26, a vane 28, a ratchet 50, and a pressing spring 52.

  The housing 24 is fitted and fixed in the mounting hole of the engine body 22. The housing 24 is provided with a rotor insertion hole 24c, and the rotor 18 is formed with a cylindrical rotary sliding portion 18a. The rotary sliding portion 18 a of the rotor 18 is inserted into the rotor insertion hole 24 c of the housing 24, and the rotor 18 is supported rotatably with respect to the housing 24.

  A rotor body 18e is provided at one end of the rotary sliding part 18a, and the vane 28 is supported by the rotor body 18e so as to rotate together with the rotor 18. The cover 26 is formed in a cup shape, and is attached to the housing 24 so as to cover the rotor body 18 e and the vane 28 together with the housing 24.

  As a result, a negative pressure generation chamber S1 as a region for generating a negative pressure is formed in a region surrounded by the cover 26 and the housing 24. The housing 24 is formed with an exhaust hole 24b that allows the negative pressure generating chamber S1 to communicate with the outside, and an exhaust valve 32 is provided at an opening on the outside of the exhaust hole 24b. The exhaust valve 32 prevents entry of fluid such as air or oil from the outside into the negative pressure generating chamber S1.

  The rotary sliding portion 18a is provided with an insertion hole 18b coaxial with the rotor main body portion 18e so as to open in a direction opposite to the rotor main body portion 18e. The intermediate drive member 17 includes an engaging portion 17a and an insertion portion 17b. The insertion portion 17b is formed in a cylindrical shape having an outer diameter slightly smaller than the inner diameter of the insertion hole 18b. The insertion part 17b is inserted through an insertion hole 18b provided in the rotary sliding part 18a.

  The engaging portion 17a is formed in a rectangular shape when viewed in the axial direction. The coupling 14 is formed in a cylindrical shape, and is provided with a rectangular engagement hole 14a that is slightly larger than the engagement portion 17a when viewed in the axial direction so as to open at one end thereof. When the engagement portion 17a of the intermediate drive member 17 is inserted into the engagement hole 14a of the coupling 14, the coupling 14 and the intermediate drive member 17 are locked to each other so as to rotate together.

  The coupling 14 is provided with a circular attachment hole 14b penetrating the engagement hole 14a. The central support member 16 is formed in a disc shape, and the central support member 16 is fitted into the mounting hole 14 b of the coupling 14. The central support member 16 is provided with an insertion hole 16a at the center thereof so as to penetrate in the axial direction, and the oil supply pipe 40 is inserted into the insertion hole 16a. An attachment hole 12b is provided at the end of the camshaft 12, and a coupling 14 is fitted into the attachment hole 12b. In this way, the vacuum pump 10 is configured, and the camshaft 12 rotates, whereby the driving force is transmitted to the rotor 18 via the coupling 14 and the rotor 18 rotates.

  The oil supply pipe 40 is formed in a cylindrical shape, and an oil passage 40a penetrating in the axial direction is formed at the center thereof. The oil supply pipe 40 is provided with a groove 40c over the entire circumference in the vicinity of one end, and an O-ring 42 is attached to the groove 40c. Further, in the oil supply pipe 40, an O-ring 44 is attached to a groove 40d provided with a groove 40d over the entire circumference in the vicinity of the other end. In this state, the end of the oil supply pipe 40 on the O-ring 42 side is inserted into the pipe insertion hole 12c, and the end of the oil supply pipe 40 on the O-ring 44 side is inserted into the pipe insertion hole 17c of the engagement portion 17a.

  Lubricating oil is supplied from the oil supply hole 12 a of the camshaft 12 to the oil passage 17 d through the oil passage 40 a of the oil supply pipe 40. A gap portion as an oil passage is provided between the end portion of the intermediate drive member 17 and the inner bottom surface of the insertion hole 18b, and an oil passage 18d connected to the oil supply groove 24a from the gap portion is provided in the rotary sliding portion 18a. Is provided. Lubricating oil is supplied from the oil passage 17d to the oil supply groove 24a through this gap. By supplying the lubricating oil to the oil supply groove 24a, the sliding portion such as the outer peripheral surface of the rotary sliding portion 18a is lubricated, and the rotor 18 can be stably rotated.

  Here, the procedure for generating the negative pressure will be described with reference to FIG. FIG. 2 is a front view of the vacuum pump 10 according to the first embodiment as viewed from the rotor 18 side. The intake port 34 is connected to a vacuum servo (vacuum braking force multiplier).

  The cover 26 has an inner surface formed in a cylindrical shape. The rotor 18 is disposed at an eccentric position in which the central axis deviates from the central axis of the inner surface of the cover 26. The vane 28 is supported at the tip of the rotor 18 so as to be slidable in a direction orthogonal to the axial direction of the rotor 18. Both ends of the vane 28 are guided by guide portions (not shown) on the inner peripheral surface of the cover 26 so that both ends of the cover 26 abut against the inner peripheral surface and slide. As a result, the negative pressure generating chamber S1 is divided into two vacuum chambers by the vane 28.

  When the engine operates, the rotor 18 rotates with the camshaft 12. At this time, the volume of these two vacuum chambers changes. When the volume of the vacuum chamber decreases, air is discharged from the negative pressure generating chamber S1 through the exhaust hole 24b and the exhaust valve 32. Thereafter, when the volume of the vacuum chamber increases again, negative pressure is generated. The generated negative pressure is transmitted to the vacuum servo through the intake port 34, and the air in the vacuum servo is continuously sucked out.

  Returning to FIG. The ratchet 50 is formed in a shape in which a cylinder is integrally fixed to a hemispherical flat portion. The intermediate drive member 17 is provided with a ratchet accommodation hole 17e penetrating in a direction perpendicular to the axial direction, and a pair of ratchets 50 are accommodated in the ratchet accommodation hole 17e so that the cylindrical portions face each other. Is done. A pressing spring 52 is disposed between the pair of ratchets 50 and biases the pair of ratchets 50 in a direction away from each other.

  On the inner surface of the insertion hole 18 b provided in the rotor 18, concave portions 18 c that are recessed in a conical shape are provided at two opposing positions with the central axis as a center. The pressing spring 52 applies a biasing force to the ratchet 50 so as to press the ratchet 50 accommodated in the ratchet accommodation hole 17e toward the recess 18c. When the pair of ratchets 50 are pressed against the recess 18 c by the pressing spring 52, the spherical surface 50 a protrudes so as to enter the recess 18 c from the outer peripheral surface of the insertion portion 17 b of the intermediate drive member 17. As a result, the pair of ratchets 50 locks the relative rotation between the intermediate drive member 17 and the rotary sliding portion 18a, and the relative rotation between the camshaft 12 that is the drive shaft and the rotor main body portion 18e that is the drive target. Locks the rotation.

  Thus, in the first embodiment, the intermediate drive member 17 and the rotary sliding portion 18a function as a transmission member that transmits torque from the camshaft 12 to the rotor main body portion 18e. In the following, with reference to FIG. 3A and FIG. 3B, a mode of locking the relative rotation between the intermediate drive member 17 and the rotor 18 will be described in detail.

  FIG. 3A is a cross-sectional view taken along the line PP in FIG. 1 when a torque smaller than a predetermined value is applied to the intermediate drive member 17. In FIG. 3A, the cross sections of the engine body 22 and the housing 24 are omitted. In the first embodiment, the predetermined value refers to a torque value at which the spherical surface 50a of the ratchet 50 comes off from the recess 18c.

  When a torque smaller than a predetermined value is applied to the intermediate drive member 17, as shown in FIG. 3A, the pair of ratchets 50 enters the recess 18c from the outer peripheral surface of the insertion portion 17b of the intermediate drive member 17. As a result, the spherical surface 50a remains protruding, and the locking of the relative rotation between the camshaft 12 and the rotor 18 is maintained. In this state, the driving force applied from the camshaft 12 is transmitted to the rotor 18 as it is, and the torque applied to the intermediate driving member 17 is transmitted to the rotor body 18e and the vane 28 as it is.

  FIG. 3B is a cross-sectional view taken along the line PP in FIG. 1 when a torque greater than a predetermined value is applied to the intermediate drive member 17. When a torque larger than a predetermined value is applied to the intermediate drive member 17, as shown in FIG. 3B, the pair of ratchets 50 is detached from the recess 18c, and the inner surface of the insertion hole 18b where the recess 18c is not provided. Abut. Therefore, in this state, only the torque generated by the frictional force between the spherical surface 50 a of the ratchet 50 and the inner surface of the insertion hole 18 b out of the driving force applied from the camshaft 12 is transmitted to the rotor 18.

  Lubricating oil for smoothly rotating the rotor 18 is supplied to the negative pressure generation chamber S1. Further, when the engine is stopped, the operation of the vacuum pump 10 is also stopped, but negative pressure remains in the negative pressure generating chamber S1, and the lubricating oil is drawn from the oil supply groove 24a and the like. Therefore, when starting the engine, the lubricating oil remains in the negative pressure generating chamber S1. For example, in an environment at a very low temperature, the viscosity of the lubricating oil remaining in the negative pressure generating chamber S1 becomes high. When starting the engine in such a state, a large load is applied to the rotor 18 and the vane 28.

  Thus, when a torque larger than a predetermined value is applied to the intermediate drive member 17, the spherical surfaces 50 a of the pair of ratchets 50 are disengaged from the recesses 18 c and the rotor 18 and the intermediate drive member 17 are relatively rotated. By releasing the lock, it can be avoided that an excessive load is applied to the rotor 18 and the vane 28.

  When the engine is started and the lubricating oil in the negative pressure generating chamber S1 is warmed and the load on the rotor 18 and the vane 28 is reduced, each spherical surface 50a of the pair of ratchets 50 is engaged with the recess 18c again, The rotor 18 rotates together with the camshaft 12. In this state, the ratchet 50 strongly contacts the recess 18c by centrifugal force. Accordingly, the rotor 18 and the intermediate drive member 17 can be firmly engaged during the rotation of the rotor 18, and the driving force from the camshaft 12 can be reliably transmitted to the rotor 18. .

(Second Embodiment)
FIG. 4 is a cross-sectional view of the vacuum pump 10 according to the second embodiment. The configuration of the vacuum pump 10 according to the second embodiment is the same as the configuration of the vacuum pump 10 according to the first embodiment unless otherwise specified. Hereinafter, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The vacuum pump 10 according to the second embodiment is provided with a cone clutch 60 and a pressing spring 62 instead of the ratchet 50 and the pressing spring 52 of the vacuum pump 10 according to the first embodiment.

  The intermediate drive member 17 according to the second embodiment is provided with an oil passage 17h that communicates with the oil passage 17d and penetrates in a direction perpendicular to the axial direction. An oil passage 18 h that penetrates from the inner peripheral surface of the insertion hole 18 b to the outer peripheral surface is provided in the rotary sliding portion 18 a of the rotor 18. The oil passage 18h connects the oil passage 17h of the intermediate drive member 17 and the oil supply groove 24a, and the lubricating oil enters the oil supply groove 24a from the oil passage 17d through the oil passage 17h of the intermediate drive member 17 and the oil passage 18h of the rotor 18. Supplied.

  A spring accommodating hole 17j that is a bottomed round hole is provided at the end of the intermediate drive member 17 on the rotor 18 side. Further, an insertion hole 17i that communicates from the inner bottom of the spring housing hole 17j to the oil passage 17h is provided on the camshaft 12 side from the inner bottom of the spring housing hole 17j. The insertion hole 17i is formed in a square shape when viewed in the axial direction.

  The cone clutch 60 includes an umbrella portion having a shape obtained by cutting the vicinity of the outer periphery of a sphere with a flat surface, and a square columnar shaft portion having a square cross section provided integrally with the flat surface portion of the umbrella portion. A spherical surface 60a, which is a part of the surface of the sphere, is formed on the outer periphery of the umbrella portion.

  A contact surface 18i that is recessed in a spherical shape is formed on the inner bottom of the insertion hole 18b of the rotor 18 according to the second embodiment. The spherical surface 60a of the cone clutch 60 and the abutted surface 18i of the rotary sliding portion 18a are spherical surfaces having the same diameter.

  The rectangular columnar shaft portion of the cone clutch 60 is inserted into the insertion hole 17 i that is a square hole and attached to the intermediate drive member 17. As a result, the relative rotation is restricted so that the cone clutch 60 and the intermediate drive member 17 rotate together. At this time, the pressing spring 62 is disposed in the spring accommodating hole 17j. The pressing spring 62 urges the inner bottom portion of the spring accommodating hole 17j and the umbrella portion of the cone clutch 60 to be separated from each other. In this state, the insertion portion 17b of the intermediate drive member 17 is inserted into the insertion hole 18b of the rotary sliding portion 18a. As a result, the spherical surface 60 a of the cone clutch 60 is pressed against the contacted surface 18 i of the insertion hole 18 b by the urging force of the pressing spring 62.

  When a torque smaller than a predetermined value is applied to the intermediate drive member 17, the rotary sliding portion 18a and the cone clutch 60 are driven by the frictional force between the contacted surface 18i and the spherical surface 60a. The rotation relative to the member 17 is locked, and the driving force applied from the camshaft 12 is transmitted to the rotor body 18e. When a torque larger than a predetermined value is applied to the intermediate drive member 17, the spherical surface 60a of the cone clutch 60 and the abutted surface 18i of the rotary sliding portion 18a slide relative to each other, and the rotary sliding portion 18a and the cone The clutch 60 rotates relatively and transmits torque smaller than a predetermined value to the rotor body 18e. In the second embodiment, the predetermined value refers to a torque value at which the spherical surface 60a of the cone clutch 60 and the contacted surface 18i of the rotary sliding portion 18a start to slide.

  Thus, in the first embodiment, the cone clutch 60 and the rotary sliding portion 18a function as a transmission member that transmits a driving force from the camshaft 12 to the rotor main body portion 18e. In this way, it is possible to prevent an excessive torque from being applied to the rotor body 18e and the vane 28.

  The present invention is not limited to the above-described embodiments, and an appropriate combination of the elements of each embodiment is also effective as an embodiment of the present invention. Various modifications such as design changes can be added to each embodiment based on the knowledge of those skilled in the art, and embodiments to which such modifications are added can also be included in the scope of the present invention. Here are some examples.

  The vacuum pump may not be a vane type vacuum pump as exemplified in the above embodiment, but may be other types of vacuum pumps. Further, an engagement hole may be formed at the end of the camshaft 12 without using a coupling, and the camshaft 12 and the rotor 18 may be directly engaged.

It is sectional drawing of the vacuum pump which concerns on 1st Embodiment. It is the front view which looked at the vacuum pump concerning a 1st embodiment from the rotor side. (A) is a PP cross-sectional view of FIG. 1 when a torque smaller than a predetermined value is applied to the intermediate drive member, and (b) is a torque greater than a predetermined value applied to the intermediate drive member. It is PP sectional drawing of FIG. It is sectional drawing of the vacuum pump which concerns on 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Vacuum pump, 12 Camshaft, 12a Oil supply hole, 17 Intermediate drive member, 17a Engagement part, 17b Insertion part, 17c Pipe insertion hole, 17d Oil path, 17e Ratchet accommodation hole, 18 Rotor, 18a Rotation sliding part, 18b insertion hole, 18c recess, 18e rotor body, 50 ratchet, 52 pressing spring, 60 cone clutch, 62 pressing spring.

Claims (3)

In a vacuum pump that generates negative pressure by rotating a rotor with a driving force applied from a drive shaft,
It is interposed between the drive shaft and the rotor, transmits the torque applied when a torque smaller than a predetermined value is applied to the rotor, and smaller than the predetermined value when a torque larger than the predetermined value is applied. Comprising load reducing means for transmitting torque to the rotor;
The vacuum pump according to claim 1, wherein the load reducing means changes the predetermined value so that the value during rotation of the rotor is larger than that during rotation of the rotor. The load reducing means is
A first transmission member having an insertion hole coaxial with the rotor and rotating together with the rotor;
A second transmission member that is inserted through the insertion hole and rotated by a driving force applied from a driving shaft;
A locking member for locking relative rotation between the first transmission member and the second transmission member;
Biasing means for imparting a biasing force to the locking member;
Have
The first transmission member has a recess that is recessed radially outward on the inner surface of the insertion hole,
The second transmission member has an accommodation hole that opens to an outer surface of an insertion portion that is inserted into the first transmission member and accommodates the locking member;
The biasing means applies a biasing force to the locking member so as to press the locking member accommodated in the accommodation hole toward the recess,
The locking member is housed in the housing hole and is pressed against the recess to lock the relative rotation between the first transmission member and the second transmission member, and a torque larger than a predetermined value is applied. 2. The vacuum pump according to claim 1, wherein when applied, the vacuum pump is disengaged from the recess and the locking of the relative rotation between the first transmission member and the second transmission member is released. In a vacuum pump that generates negative pressure by rotating a rotor with a driving force applied from a drive shaft,
A first transmission member having a first pressing surface that rotates with the rotor;
A second transmission member having a second pressing surface rotatable coaxially with the rotor, and rotated by a driving force applied from a driving shaft;
Biasing means for biasing one of the first transmission member and the second transmission member toward the other so that the first pressing surface and the second pressing surface are pressed against each other; With
The first transmission member and the second transmission member are
When a torque smaller than a predetermined value is applied, a relative rotation is locked by a frictional force between the first pressing surface and the second pressing surface, and the driving force applied from the driving shaft is applied to the rotor. Communicate to
A vacuum pump characterized in that when a torque larger than a predetermined value is applied, the vacuum pump rotates relatively and transmits torque smaller than the predetermined value to the rotor.

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